I'll give you some advice that's contrary to what you're getting on this thread: make a commitment to finish a certain amount of books by the end of the month/year and dont start a new book until you finish the one you opened.

What it comes down to is a commitment. If you set a clear goal you'll feel pressured to keep up/bad if you fall behind. If you don't start a new book then you'll want to read the one your on faster in order to get through it. You have to make the conscious decision to put down your phone and read but it gets easier the more you do it.

Might also help if you read nonfiction, classics, or popular novels? That way you can talk to other people about it and be in the loop with your reading ("I just learned x" or "now i get that reference to y" or "I also read that new book/I need to finish this book before the next one comes out")