If you want to improve the rankings on your website on Google, it is often much easier to improve your existing backlinks than getting new links to your website.
Step 1: Correct links that point to your old domain names
If you changed your domain name in the past, chances are that some people still link to your old domain name.
The links to your old domain name should redirect to your new domain with a 301 redirect to make sure that the links and the visitors that come through these links aren't lost.
Unfortunately, backlinks through 301 redirects do not pass the full link power to your website.
For that reason, contact the webmasters who link to your old domain name and ask them to link to your new domain. This will increase the effect of the links on your website rankings.
Step 2: Correct links to broken pages on your website
Check your website statistics and redirect all links that go to a non-existing (404) page on your website to an existing page on your site so that the visitors aren't lost.
As above, it's even better to contact the webmasters who links to the non-existing pages and ask them to change the links.
Step 3: Try to improve the anchor texts
When you're contacting other webmasters to tell them that they link to your old domain name or to a broken link on your website, you can also suggest new anchor texts for your links (the anchor text are the words in a text link that points to your website).
If the links to your website include the words for which you want to get high rankings in the anchor text, your chances of getting ranked for these keywords increase.
Step 4: Suggest other relevant websites (not so strange as it seems)
This might sound like a strange advice but it can help your rankings: when you contact a webmaster and ask for a link, you might also suggest other websites that are related to yours.
If the website that links to your website links to other websites that are related to your website topic, it's more likely that search engines will find your website relevant to that topic.
Step 5: Check the links and the navigation on your own website
If you want to see certain pages of your website in Google's search results, these pages should also be linked from your own website pages. If a web page is hidden in the navigation of your website then it's less likely that this page will get a good position in Google's results.
Your website should have a clear and logical navigation that emphasizes the pages that you want to see in Google's search results.
High rankings on Google are the result of good inbound links and optimised web page content.