How to realize small waking periods

How do people learn to realize the small waking periods between dreams, it would be kind of hard, because I cant even remember them, let aloe realize them while they happen

The water method works. Drink a lot of water before you go to bed,and each time you have one of those small awakenings, it'll become a full awakening because you feel like you need to go to the bathroom. It works.

And then eventually I will just get used to it?

To get yourself used to it, try a mantra like "I will wake during every REM period" (or during every dream). What worked for me was that I wrote this in my DJ before I went to sleep, and I guess that helped to impress it into my mind. Since then, for a long time afterwards (like many months) I always woke up remembering a dream I had just had. Try combining the two methods at first, so the physical stimulation will ensure you wake up.

We all wake up, we just barely reach concious. You can teach yourself to remember when you do wake up, the easiest way to remember is every time you do actually wake up, make sure you get it into your head that what you did was what you wanted to do. Does that make sense?
Hope it helps.