How can i improve my English ?

Seriously, guys i really wanna know how to improve it when trying to write a paragraph.
I mean what do i need ?
I heard people say grammar but where should i start it?
I have problems in ponctuation as well..
And how long will it take me to learn that ?
And thanks for your support !


td:rt : I speak english pretty well !((American Accent)) but i write it like man living in a cave.. I would apperitiate your help, thank you.