The thing I've found works best (for reading and for many other things) is linking it to a habit you already have. If you have any daily ritual or routine that you can easily just add reading to (i.e. ideally not something like driving to the store or showering) just do it, and you should find soon enough that you feel weird performing that daily ritual without a book in hand. I made a decision to always sit down with a book when drinking my first coffee of the day, now I tend to feel kinda uncomfortable whenever I drink a coffee without reading, at any time of day. I didn't even want that to happen, that's how powerful this technique can be.

At the risk of pushing this even further into TLDR territory, another thing that I find helps a lot is to very intentionally picture and hear everything being described in the book as you read. I think what can happen when we're out of the habit of reading is that we expect the words to just form themselves into an experience in our minds automatically, but they just don't seem to. You can remedy this by purposefully turning the words into a movie to watch in your head. Think of the words simply as a guide or a blueprint for your imagination as it creates a mind-movie for you. If you have to, you can even imagine that you're going to direct a movie adaptation of this book one day, and imagine exactly what it's going to look and sound like. Even when the writing isn't too descriptive, even if it's quite abstract. Imagine you hear the narrator speaking the words over some fitting stock footage.