I actually don't think pacing is my problem. For instance, last night's blitz game was 15 minutes, and I had about 3 or 4 minutes left in the endgame when I blundered. I didn't move too quickly early on and blunder, but I also didn't use so much time that I had nothing left for the endgame. That's pretty good pacing, I think.
I've gotten good enough at my openings that I can make those moves quickly. And as I said, I'm working on endgame technique so I'll be able to play those faster without thinking. And I can spot the really obvious tactics pretty quickly these days, after doing tons of tactical puzzles along the way. I'm a little slow on calculating tactics that require calculation, though, but that's not a major complaint.
My problem is really just that I blatantly blunder when I get into time trouble. Hanging my rook last night is a perfect example. I've done similar stuff in other games, either slow games where I get down to 15 minutes or less on my clock, or else when I try to play faster time limits. I just need to find a way to force myself to blunder check for 2-3 seconds before making a move, just to make sure I don't blatantly hang a piece or something similarly stupid.
--Fromper