This seems to be a cicada thread. But the previous generations are closed and there has been some recent discussion in the DL forum (my fault), so I thought I would bring it back again to collect them.
This started with a side comment of mine.
My experience is that it isn't really that hard to tell. If you don't know you are lucid dreaming, you aren't. If you can fly in your waking world, don't bother dreaming about it.
Having said that, I don't know how to make it happen. For me it was a response to traumatic dreams, but I don't think that is an attractive approach.
With respect to sleep paralysis, this is actually one of the things that led me to intervene in my dreams. Sleep paralysis is normal. (Essential. Without it you do things in your sleep that you really don't want to.) Being aware of it is not. But if you are dreaming, you can do something about it.
One repeated aspect of this, for me, is dreams in which I can't move my legs. (You've had those, right?) My reading of this is that it is a partial awareness of sleep paralysis. After I got good at changing what was happening in my dreams, I arrived at a number of work-arounds. My favorite is realizing that I can skate along a few inches off the floor, sort of a cross between Gumby (before your time) and a hoverboard. Other times, I realize that I can push myself along with my hands, again a kind of skating along the ground, but on my butt.
To be clear, I was modifying my dreams for a _long_ time (from something like five years old, or so, until my mid-20s) before I realized what I was doing. That's when I started asking myself what else I could do and doing it on purpose.
So I would say that if you've ever had one of those paralyzed dreams, you're already close. You just have to find enough motivation to change it.