This ia a topic which is generally not well received on the board. It's one I struggle with as well. I can't offer you tried and true ideas, but this is what I'm trying.
It came about because of a practice match on Sunday for the club championships this summer. I eeked out a tie-break win in the first set playing the way I mostly do which is "oh, here's the ball, she's there, I'll hit it it the other way" IOW, no real plan, just reacting to the situation of the moment. On the change over, I decided I really didn't like her forehand, so I would hit everything to her backhand. I made 50% fewer unforced errors, her backhand fell apart and I won 6-2. Sooo.... I sat down and thought about how I've made points in the past, what I do well, etc. and came up with the following list:
My basic style of playing is aggressive baseliner with the intention of coming to the net (i.e. I don't try for winners from the baseline, but to force short balls)
1) play every shot to one side (and then surprise them by playing to the other)
2) Run them side to side
3) one long, one short (lob or pass)
Then I thought about the serves and serve returns which I can hit which would be best for each option.
So the next match I play (Saturday, the indoor masters (!)), I'm going to pick one and see how it goes. At the least I expect that my unforced errors will be minimized.