It's easy to find yourself on a Friday, looking back and wondering where the time went. Work hard to raise your own expectation of how much work you accomplish in a day.
Amen, sibling. Perhaps this is something so trivial/obvious that the OP decided it wasn't worth mentioning, but a good personal time tracking system is essential; it gives you feedback (why can I only account for 4 hours of my workday? Time to cut down on /.!
) and data for your employer (I spent 15 hours last month maintaining product X; perhaps we should fix those bugs?