1. Doing a reality check habitually in real life. Eventually you'll start doing it in dreams and have it fail. This _usually_ kicks you into lucid territory
2. Estimating when you're going to be in a REM state and setting a timer to wake yourself up. Then, after gaining consciousness fully, trying to make your body go to sleep while your mind is awake
Can you spot why I stopped doing it after a period of time? It end up feeling like a lot of work every day just for a chance (a low one in my and most people's cases) of having a lucid dream. Sleeping was no longer a passive, let's-relax type of activity. I just wanted to reclaim that period of time in a way.
I think my biggest takeaway from my lucid dreams was just the feeling of being in one. It's hard to describe, but the rush that comes along with the realization you can do anything you want is quite exhilarating.