I cant stop staying up at night?

Exactly as it says on the tin, I cant stop staying up at night, no matter what i do i always seem to stay up well past even 3 or 4 am. Its just if i try and go to sleep at a normal time like 11-12 i find it hard because i think i may have sleeping problems. it takes me for ever to get to sleep, i need to be totally wreecked before i can doze off, any ideas on helping me?