Good question

how do i become a gamer?

play lots of games, try new ones and expand your taste

you touch your peepee

>>>/mu/

You don't, just like the 'tism you have to be born with it.

GOD DAMN IT NILE QUIT TRYING TO FORCE THIS

Immerse yourself in games and gaming to the point where you make sacrifices in other areas of your like for the sake of supporting your hobby

You start by committing suicide.

Do you play games?
Do you like playing games?
Do you play a wide variety of games?
Do you find it difficult to imagine your life without games?
If you answered yes to all of these, you're probably a "gamer"

If you use the word "gamer", you're probably a massive fucking casual normalfag who is responsible for killing video games.

That's why I put it in quotations. It's a marketing term at this point. I only used it to answer OP's question.