Sharpening Concentration and Focus
Your brain is just like a muscle and needs to be built up to work better. Things like meditation where you control your breathing can assist in training your brain.
Clarify what you are getting done and what you want completed by the time you are done working.
Put a deadline of when you want to be complete with what you are doing. A lot of times this helps you concentrate more on what you are doing and speed up the process.
Sometimes when all else fails you need to just get away from everything to be able to clear your mind and have complete focus.