How to improve my backlinks?

The question doesn’t make a lot of sense to me, but to take the title of the question:-

You can’t really do anything with backlinks, as true backlinks are not yours to do anything with, they are created by some unrelated third party.
Any “backlinks” which are yours are not backlinks in Google’s eyes.

Here is a related topic that may interest you and save us the teduim of repeating all this once again:-