It sounds like a simple psychological trick, but it's incredibly effective for cutting down on time-wasters like watching television. The advice? Make wasteful activities more difficult to do.
If you want to spend less time watching TV, you can put the remote in the garage for a month, or put a wall timer on the TV that automatically shuts it off every night at a certain hour. Even unplugging the TV so you have the find the cord and plug it in to use it will help you reduce the time spent in that activity, since you can't as easily do the activity mindlessly.This trick can work for lots of other wasteful activities. If you lose track of time on Facebook, unplug your DSL for a while. Better yet, block your own access to a Web site. Have a tendency to sleep too late? Keep the curtains open so the morning sun make snoozing tougher (or you'll have to get out of bed to close them). Spend too much time gabbing on the phone at work? Set it to go directly to voicemail, check it once an hour and return only the important calls.
Of course, none of this guarantees you won't take part in time-wasting pastimes. But at least you'll have to make a conscious effort to do so -- which means at the end of the day, you won't be left wondering where all your time went.