Years ago I did the one day Franklin Covey "What Matters Most" course. So named because you can't change the number of minutes in any day and so cannot manage any more time out of a day but rather need to work on setting priorities. I found it very interesting and still use some of the techniques we went through. Without buying all of the expensive kit that comes with it, that is. Stephen Covey also wrote the 7 habits of effective people, haven't read that but might be worth a read. If you have the money and the time (a day) you could find out if those courses are still on offer. It was organised through work for me so I don't know what firm did it.
The main thing I use from that course is the organisation of my to-do lists. Top thing I remember is to always end your day by writing your to-do list for tomorrow. Starting the morning by writing a to-do list doesn't work because you'll already have forgotten half of what was going on yesterday. Write a list of everything that needs to be done and then mark every task A, B, C, D where A is stuff that must be done, B would be good to get done today, C needs to be done but could wait, D can wait (I'm paraphrasing). Then, for each category, mark the tasks in order 1 to 10 (or whatever). Then start with A1, move to A2 and so on. If you get through all the As move on to the Bs. Things that are category C today will make it up to category A in a few days if you haven't gotten around to them, for example.
Hope that helps.