In SEO Link-building is given major importance as most number of traffic is generated through link-building. It comes under the off-page SEO techniques.
1.From where we can get back-links:
a) Blog Posting
b) Article Submission
c) Directory Submission
e) Blog Commenting
f) Social Media like Facebook, LinkedIn etc
g) Press Release
h) Paid Links
2. Always get back-links(link on other website redirecting to our website) from relevant websites. As it will give more value to your website. Getting back-links from irrelevant website will give a less values hence no chances of getting on search results first page.
3. Check the domain authority and the page authority of the website where you will be doing link building.
If the domain and page authority of the website are high, then good values will be given to your website by the search engines as the back link is coming from high domain authority websites.
to check this go to opensiteexplorer.org and enter the URL of the website.
4. While doing link-building don't just copy the websites URL. Pay More attention to your targeted Keywords and include that keywords in the anchor text and in href add your website URL or the page of the targetted keyword.
<a href="www.myseocompany.com/seo"> SEO </a>
5. The maximum the number of traffic your getting through link building means the more link popularity.
And your website would get regularly crawled.
6. Getting back-links from sites relevant with your website is of more value other than getting back links from some other different sources. i.e If your running a website on seo services and your getting back links from an restaurant website then search engines would give very less value to your website.
7. Link-building is important in SEO, as it will determine the popularity of your website which will indicate search engines that its good site and thus will play a major role during the ranking in search engine results.