On the chessboard, do you have problems with time pressures and making not just tactical mistakes but outright blunders under these conditions?
People make mistakes all the time. You, me and every living breathing human being on the face of this planet.
I make mistakes all the time, some so dumb it beggars belief.
These errors came about because of (usually) incorrect analysis of the position and tactical oversights due to either time pressure or impulsive thinking.
I can't speak for everyone but I found an improved training method that I like to share with everyone whenever I'm on "Tactics Exercise Day".
Previously, I set up maybe 45 minutes on my watch/timer/clock. And pick up my rusty tactics book, namely, Reinfeld's 1001 Brilliant Ways to Checkmate and work out 30 puzzles from there. In each position, I try to write down (as fast as I can) on a piece of paper, the best line I can think of and any side variations of up to 2 moves (4 ply) ahead.
But recently, I discovered a much more efficient method.
I downloaded Reinfeld's 1001 Brilliant Ways to Checkmate file from Chessville and load it into Fritz 11 (yeah, yeah I finally gave in to the temptation). And what I do is clear out any of the continuations and save them to Chessbase format.
Fritz 11 has a very wonderful feature called "Calculation Training". For more information on this, please read Chessbase articles part 1, part 2, part 3 and part 4. In Fritz, I use this Calculation Training feature to make my moves and suggest counter-moves and responses. In this way, I can insert moves until I'm happy that I've got a winning position and move onto the next problem.
After I'm done, I check which lines I've missed. Now I work on the next 30 puzzles and repeat ad nauseum.
Once I've finished the 1,001 puzzles, I plan to start from the beginning and go through again (or if you prefer, you can work through the same 30 problems until you ace them all before continuing on the next set. YMMV)
This practice allows me to analyse quicker, forces my mind to react faster, and essentially "programs" my brain to quickly identify when tactical situations arise.
I am not suggesting this is the best way but I find that this way works out well for me.