It will take time and effort, and with only 5 days as a WordPress.com user you can't expect to be the world's most famous blogger already. ≥^!^≤
Have you worked through the tutorial about how to use the WordPress.com platform yet? It is very useful for getting yourself oriented to how things work here: http://learn.wordpress.com/
Tags and categories are very important for getting Google juice. But it will take time, 6 to 8 weeks, before you start seeing readers finding your site. Please read the links I gave you about increasing readership as well.
…google's number one but unfortunately i can't do this :( …
Well, I don't know you, so perhaps it is true that you cannot do it. But perhaps you also don't know yourself until you try. You got something more important to do? I mean like a goal? So what, you start small and build up to something bigger.