That is a large question.

Meditation is the art of controlling and cultivating your awareness. And by awareness I mean what you direct when you pay attention, what you concentrate when you concentrate and what gets jerked around when you are distracted.

We basically have 2 techniques. Briefly.

The first technique is “concentration” (it goes by different names). Hold your awareness upon a thing as perfectly as you can for a while. One good thing for this is the feeling of breath in the tip of your nose.

The second technique is “vipassana” (it also goes by different names). Watch all these experiences that you are having right now. All the sights, sounds, thoughts, etc. Watch all that and also watch your awareness. When you feel like you are about to react to all that by directing your awareness at this or that, to concentrate, to think, to enter a daydream, don’t do it. Just refrain from doing anything like that. Just keep watching and keep your cool.

The first technique is dead easy, just takes perseverance. Pays off fast. Shows you what we’re dealing with, with this “awareness” thing. It’s educational that way. We generally get good at the first technique then try the second technique (which is trickier). The first technique can also be used as prep for the second technique. It works very well for that. Makes it stronger.

Meditation makes you smarter, it gives you energy, it opens doors and windows that you didn’t even know were there. And there’s a lot there. It gets you high too.

(Ok, specifically : Concentration improves your ability to concentrate. Improves your memory. Makes it easier to get things done. Makes your thinking sharper. Makes your willpower more powerful. Pumps up various crafty powers like art and software dev. And as for vipassana. It makes you happier. You start lucid dreaming. You become better with people. You become more aware. Your reality gets bigger.)