I think it's easiest to see energy in the dark. When you're in your bed about to go to sleep, or in a relaxed state of mind, start moving your hands slowly back and forth from each other about a foot above your eyes, and you can usually see traces of energy coming off your fingers. Just focus on the area between the tips of your fingers, as you do it. It looks like the smoke of a cigarette (and I don't smoke or do drugs so it's not that, lol). It's a smoky transparent hue when I see it.
It kind of looks like this, but not as bright, and it's made by your fingers moving:
I also sometimes see green & purple balls of energy circle/spin around me when I'm in meditation or doing breathing exercises. When they appear, I can see them with my eyes closed or open.