Location! Where you write is critical. Leave the house. My favorite place is the library. If you can’t leave home, set up a dedicated writing place where distractions are minimal.
Write on (a) schedule! Plan to write for a certain amount of time without stopping – shoot for at least an hour. Then take a break, stretch, use the bathroom, grab a snack. Your break should be only 5-10 minutes. Then back to writing.
Disconnect! Turn off your Internet connection and cell phone. The temptation to check emails, FB, twitter, and texts is hard to resist and will slow you down. If you have kids, keep the phone on. Children are more important than your word counts.