1. Start and finish it - every time you break up an activity with another you loose focus. Getting back into the right frame of mind takes precious time. By all means divide large projects into smaller chunks, but complete each chunk with as few interruptions as you can.
2. Take breaks - at the same time you, you need to build in breaks (at suitable points) in order to regain efficiency. You might think you do your best work when you are exhausted and high on caffeine, but sadly this is when most mistakes occur.
3. Time busters - identify the activities which steal your time, but add no value to your life. These might include driving and parking when you could take a train, watching TV programmes you don't enjoy or poorly organised filing system.