First key is to be sure to calculate all forcing moves just a few moves deep. Mostly captures, checks, and mate threats. If one capturing sequence doesn't work, change it a little to see if that helps. If a move looks suicidal, but it threatens mate, it's still useful to check it just 1 or 2 more moves.
There are types of positions where tactics are more likely (and less likely). Hanging (or poorly defended) pieces and/or an exposed king are some basic signs tactics may be present.
i have been doing alot of tactics trainer and i think that i am getting reletivly good at it. however I am having severe difficulty applying these new skills into actual games! so here is the question... WHEN DO I LOOK FOR TACTICAL OPPORTUNITIES! what signs should i look for? when are they most prevelent? how do i look for them? what questions should i ask myself when executing a tactic? how do i improve my tactical vision? hope this makes sense! ANY advice will be much appreciated! :)