For me, if I've done enough tactics training, it just becomes natural. The more you practice, the more evident the patterns become and the less time it takes to identify them.
If you haven't spent much time doing tactics, then inevitably you will take longer to find the correct sequence.
It's like anything else in life, you put enough time into it and you'll get better. Then when you go to play games (not actively looking for tactics), you'll find them anyway out of wrote habit.
How long do you search for a tactic during a game? While working the Tactic Trainer, I found myself spending quite a while looking for a tactic that was somewhat deep. Then I realized that unless there were some clues (ie undefended piece, weak back rank, poorly defended King, etc) I would never spend as much time during a game and therefore I probably miss a lot of tatics.
How long do you look if there isn't an obvious tactic?