Sugar Cube, you asked for tactics, not technique, so i'm going to put my toe in the water and offer up some tidbits that have (and still do) help me. (mind you, i'd never presume to give advice on technique
past the beginner stage!) Please know that i'm just a fellow skier, not an uber-instructor like many of the folks on this site or thread, so take whatever seems right and ditch the rest.
Ghost's suggestion to find some soft stuff on the side to practice in a 'safe' place was a good tactic.
Along that line, find a slope with good pitch and cruddy conditions that you normally avoid, but one that is wide and short. That is a slope you can easily see the bottom of so that even if you had to straightline it in an emergency (which you won't), you will be OK. That will give you the confidence to try the relaxing thing suggested above. It doesn't really tranlate from being able to relax on easy terrain to relaxing on scary terrain. So you try to make the stuff on which you are normally not comfortable less frightening. that way you are practicing in the actual conditions you want to ski. (IMHO, this is more productive to what I think you are looking for than practicing more turns on the groomed, although that's undoubtedly good for technique issues.)
Same thing for the bumps. Lito has a dvd on bump and powder skiing that takes it down to very simple easy steps and he says, go find some 'bimps' to practice on. Good idea. See if you can find one of those short slopes with bimps on it to get some speed in the bumps which will help with the turning. If you are frightened and try to ski them too slow (think stop or almost stop at each bump) it's harder than finding some flow, even if it's only three bumps at a time. If you can't find a short slope with bimps, look for one that is half groomed and half bumpy. (although those are normally not as good as a regular bump run because they attract so many novice bump skiers like us that tend to screw up the bumps on the edge, making them actually more difficult to ski! but it'll do in a pinch.)
Trees. The opposite. decide to ski around one or two trees at a time only and then stop or almost stop. Give yourself permission to do this. Then go ski the same line over and over again until you can ski it more fluidly. Then start another line and do the same thing. Pretty soon you'll be able to "see" the lines or spaces form as you ski and it will become easier to link a whole tree run.
As good as it is, sometimes the slow line fast is not a good idea in the trees because you need time to decide where to ski in the trees, especially at first and because sometimes there's wood smack dab in the middle of that slow line! so you also have to be able to ski the fast line slow
. That could mean anything from skidding to pivoting to even a braking wedge
:. That's OK. Have you ever watched extreme skier competitions? Those guys stop, sideslip and do all sorts of stuff that would be a no-no on an MA thread. That's for survival. If you are on your own personal 'survival instincts kick in' terrain, then it's OK for you to do that too until you get more used to it.
Hope that's helpful. If any of this seems like bad advice or worse, dangerous, i hope one of the more senior posters will correct it.