How to build backlinks for seo effectively?

 Link building gets 50% weightage in terms of ranking. Here are the main elements that decide how good your links are and can be considered as pre-requisites of link building

1. Dofollow or nofollow - Dofollow links are preferred but very rare and difficult to obtain. Nofollow links are easier to obtain but their volume has to be more to offset the less weightage. Typically a ratio of 3 to 1 for nofollow to dofollow is fair to get you good traction in search results
2. Domain authority (DA) of the website from which link is obtained - It is recommended to get from websites whose DA is greater than your website. That being said, it is also recommended to have links from websites of a wide range of DA. But the lowest can be 6
3. Anchor text - this is the text phrase for which the link is given. Having a keyword as the anchor text can help improve ranking much faster than normal. The most common anchor text option given by websites is click here and no text at all (naked links)
4. Position of the link: Always try to get a backlink to the website in the first part of the content - both Google & users take the links in the first paragraph more seriously than the ones at the end
5. Links per domain: Do try to get more than 20 links from a single domain at a time and definitely not to the same page or same bunch of pages. This is taken as link spamming and a penalty can be applied too
6. Trusted sites only: Any site with a spam score over 10 is to be avoided at all costs. Similarly, sites without SSL, traffic or very low DA score too are to be ignored for link building purposes
7. Outlinks: As much as links coming back to the website is important, it is also important to link back to highly relevant and important websites of high DA
8. Generic & useful content: Content used for link building purposes cannot be too self-promotional and should aim to be useful for the readers
9. Grammar & silly errors: One of the most avoidable yet very common reasons as to why content gets rejected is Grammar errors and typos or addressing the concerned person name with a spelling mistake or with another name. Please avoid these errors to improve the conversion rate of outreach to links. Use tools like https://www.voilanorbert.com/ to identify the right email address, as not being able to even send an email to the correct email address is another big low to avoid
10. Subject lines: The email templates and subject lines have to be highly customised and specific to the person you are sending the email to. Unless your email gets opened you are not likely to get any link back
11. First 80 characters are all that you have to impress the reader of your emails. That’s the first 5 seconds after opening your email. Most people drop off after that if they didn’t like the first line
12. Online social presence: If your brand does not has a good social presence most websites are going to ignore your efforts. Instead, a strong social presence makes them interested in you and likely to link back in hopes of getting traffic from your social followers
13. Author profiles: Most websites have blog content but there is no insight as to who the writer of the content is what they do. Having author profiles on the website which gives a brief bio about them along with their social channels can help build authority and trust not just with people you are asking for links but also for Google (Google has something called as E-A-T)
14. Internal links: Having a good URL structure and great internal linking will help in getting people to stay on your website longer and also build hierarchy within your internal pages to help with ranking
15. Content: Product content regularly and in different formats to publish on your website

There are various kinds of link building approaches, of which the most common and popular ones are discussed below:

1. Citations: These are crucial for Local SEO. They need not have a link back to the website but the main objective is to have the Name, Address and Phone number correctly mentioned and if the possible reference to the website. Though they are not always having a link, the approach to get local citations is very similar to directory submissions or guest post link building. Hence, citations are also a part of link building
2. Directory submission: By far the easiest way to get links is to submit to company directories or phone number and local business directories. They get a good amount of traffic and are highly relevant to their end-users resulting in relevant traffic to our website 
3. Guest posting: Industry-specific websites are to be approached with content valuable for their readers and get a backlink for the relevant keyword to your website. Buzzstream is a very good tool to execute guest post outreach
4. Competitor link building: Check out the backlinks your competitor is having from Ahrefs or SEMrush. In fact, first, approach the lost backlink websites with your content
5. Content repurposing & outreach: People consume content in different manners. Some prefer video while some prefer audio. So if you have written a great blog post, create content in video or podcast format with someone else and get a backlink from their YouTube channel or podcast description. This works wonders in getting more new audience to your website. Similarly, content can be repurposed into other formats as well and pushed out on different portals
6. Influencer outreach: The easy way to execute this is by mentioning a big influencer in the industry in your content. Add your opinion and explain the influencer’s impact in the industry. Once that is done reach out to the influencer about it. If even one of the links back to your website from their social media or website, that would have a huge impact on traffic that is driven to your website. This technique is also called Ego bait (quite correct to be honest)
7. Broken links: Most popular websites have broken links. It's just normal that with huge amounts of content being published, some of it goes missing and a broken link is generated. So shortlist popular websites from your industry. Find their broken links. Prepare content that would be the right fit for the missing link and approach the website/publisher with your highly relevant content and ask them to link back to your content instead of the broken link
8. Lost links: We would have built links based on the relationship with other websites or participating events together, etc. Over course of time, things may change on the associated website and they might end up removing content linking back to your website. This loss in backlinks can be taken as an opportunity to rebuild relationships and approach them to get back the content on their website or offer to do something more relevant for the current times. This usually helps get back the link
9. Brand mentions: Some of the websites on the internet might find your content or product or service highly valuable. They will go about creating content on it and then mention your brand instead of giving a link back to your website. Such brand mentions too can be approached and easily converted into a backlink.
10. Image links: There are many websites which search for images and then pick the ones they like and use them in their content. Some of your images too might have been used like that. So a simple reverse image search of all your original images on the website can help you find such websites. Instead of doing a copyright claim or DMCA takedown ask them to attribute the image to your website and get a link back
11. Lists: Many websites have content talking about lists of [product/service] in a city or other themes. What we could also do is find lists about our industry and get ourself on the list. This way, you can easily get highly relevant traffic to your website
12. Blogger outreach: Though blogging has gone out of fashion, there are still many reputable bloggers in each city. Select your cities of operation or brand presence and get bloggers in those areas to talk about your brand. You can offer them content in infographics, video, podcast or as images which they would not otherwise have access to on their own. This way, it will be easier to get the blogger interested and in getting the link back to our website
13. Skyscraper technique: Find out the best content item in your industry. Write something much better than it and approach relevant publishers citing that this is much more authoritative and better than the current existing top content
14. News, PR, Contests, Discounts and Events: This is one of the most valuable and easy ways to get backlinks as well as traffic to the website. Take part in events, conduct contests and ask news + pr to talk about it. The reach such obtained is very high
15. Publish downloadable ebooks: Useful ebooks that are published for people’s benefit not only give a link back to the website but also help in increasing the brand image or worth
16. Market updates, reviews and testimonials: Having good testimonials and reviews on popular review portals will eventually end up being great backlinks to the website
17. Social media outreach: All links from social media are nofollow links but a reshare of your website’s link with relevant brand mentions or keywords can go a long way as they are high traffic and DA websites. So get as many social media users or influencers to reshare your content as possible
18. Blog & forum commenting: Reach out in relevant blogs and forums and add a link back to highly relevant content on your website 
19. Contribute to PR/Publications/Roundup blog posts: Some publishers like to collect industry perspective and do round-up with all related people. Try and contribute to such publications and insist on getting a backlink when mentioning you or the brand
20. Create RSS feed of your blog: There are many scrapers and feed readers still functional which pick RSS feed content along with links and publish them. So having proper internal links
21. Sponsor/Donate or buy stuff: Crowdfunding sites give a link back to your website in case you purchase from their featured products. Similarly, sponsoring helps gain links from the event organisers
22. Job postings: Jobs get recirculated a lot more than normal and they all eventually have to link back to you
23. Q&A & other crowd contributed content sites: Quora, Imgur and GIPHY are good examples
24. Ask customers: If your customers have a website of their own, asking them to have a testimonial for you on their website or a recommendation
25. Outdated content: Find out content which is based on outdated content or legislation or laws. Approach the website owner with relevant content for a link back to your website
26. Content syndication: Republish your existing content on different platforms and link back to the relevant section/page of the website
    

Hopefully, these will help you in your quest to Linkbuilding.