I think the best you can do to your productivity is to develop the routine of working, not trying to force yourself not doing something like visiting Facebook.

When my brothers got bad grades on school, my parents took away the games console, but my brothers started playing on friend's houses, so my parents forbade them to go out, so they used the computer(the one supposed to be for working) to communicate and spent most of the time there.

You can block anything and you will stare at the wall dreaming away. If your body does not want to work(for example if you try to work so much that you exhaust your body without time off) your body wont work at all no matter how hard you try(burn out).

The unconscious does not know about negatives. Do not focus on what you want not to do, but on what you want to do.

Also, take it very seriously taking breaks and resting. Most people in IT overextend and get burned.