'Urgent' vs. 'important' is useful but incomplete.
Though it's not without its flaws, Getting Things Done by David Allen is at the least a good starting point to personal time management.[1] I also recommend Thomas Limoncelli, Time Management for System Administrators, which addresses specific requirements of many tech workers (programmers too).
http://shop.oreilly.com/product/9780596007836.do
From Allen, particularly, the notions of different levels of task (he uses flight/elevation metaphore for Immediate to life-long goals), and of regular review. Information capture without review has very little value.
My first problem with the genre generally is that it seems to presume everything can get done. Actually, no, it cannot, the attempt will burn you out or kill you (see the FT burnout article I'd submitted earlier: http://archive.is/OQSTS). But your planning/tracking system may well (and really should) help you discover your pace, rhythms, limits, and warning signs.
Allen shares my general disdain for computerised trackers. I've settled on bullet journal and index cards, mostly, though I'm still developing my system and tuning it.
Another issue is that many "tasks" really aren't; they're goals, aspirations, large projects which have not yet been analysed, assed, broken down to subtasks, and/or abandoned. Even apparrently trivial items can take far longer than anticipated.
Your personal community -- at work, home, social, commercial, political -- has a tremendous influence. If you are constantly facing opposition or at best apathy to even basic goals or needs, any progress will be exceedingly painful. Changing environments is almost always easier than changing peoole, though if you find the situation unchanged even in new environments, consider looking at yourself and how you respond. My first approach is generally to try to work with or accommodate others, but I'm getting far quicker to push back and demand what I need to function and succeed. That's often the only thing that works.
________________________________
Notes:
1. Though in fact took me nearly ten years to get Getting Things Done done, no joke.