Guild Wars 2

I increase my level very little, but I want to know how can I do more in the game.

Just keep playing, u will eventually figure things out.

Well, your first goal is to get to lv 80 with a profession that you love.
To get there, you can do heart quests, personal storylines, gathering and crafting, dungeons, exploring, and so on. You can also do some wvw, though you will not be so good at it at all for awhile.

Also, join a guild.