Put on some chill music, make sure you're comfortable, and get at it. Might be slow going at first, but you'll pick up the speed.
In extreme cases I put a made-up proxy into my browser settings so I cannot surf the internet without being reminded I have other things I should be doing. =]
When it comes to writing something, I cannot write it on my computer without quickly losing interest. So I take out a pen and pad, and go into a quiet room as far away from distractions as possible.