Good niche, good keywords

Monetizing, Advertising & Marketing Marketing Methods
1

How get a good niche for my games and a good keywords
for more downloads

2

I think you can test with google webmaster tools.

appbrain also have a keyword analyser when you have completed your desciption

3

I see you have mentioned appbrain website. I see this site. It has many good apps and works good. I hope i will research about it in next time.