For me, the best writing aid is routine.
I got into the habit of getting up at 5am, doing some exercise and stretching, and then coming along to Macdonalds to write (cheap coffee, free wifi, free parking and virtually empty). Most mornings are quite productive in terms of writing, but even those that are not are still good because I can get all my admin done.
Routine is the key. If I can do it regularly, without having to think about it, it takes the pressure off, it gives me creative space. Then the rest of the day is freed up for the business of living.