I try and workout the angles first. ie.
Left armer - how much turn, flat/quick or slow/loopy, attacking middle or off?
etc
Dictates my shot selection. A flat bowler can be more easily hit through the line with a straight bat, a leggie turning it square might require cutting and sweeping.
Tend to play the line of the ball to the offie, which allows for the turn to hit the pad. Theory being that your foot is outside off if it turns back onto the stumps or if it's on the stumps, it'll turn down leg. Also sets up the slog sweep if it's turning big and he has to pitch outside off to hit off.
Left armers I'll play slightly outside the line, allowing for a little turn. The angle makes it tougher for LBW's as the ball has to straighten, in which case I have it covered. Looking for the sweep down leg or the cut and drive if the room is outside off. Leggies I'll play in a similar fashion to left armers.
I generally don't go down the track until I'm in and sussed the bowling pace/spin. Tend to do it now and again, to often makes it predictable and you're likely to come unstuck.