I agree with others. In 8-ball you should plan the out backwards. Sometimes you can't really see that far in the future, since clusters need dealing with first. If that's the case, get to the cluster as fast as you can, and then once it's open, plan the rest of the out backwards.
In 9-ball, there's really no reason to "plan the run" at all; the order of the shots is already dictated. The 3-balls-ahead rule is what you need. If you're on the one, figure out, based on the position of the 3, what angle you want on the 2. Get that angle, and then figure out, based on the 4, which angle you need on the 3. Rinse, repeat.
The exception to this is looking ahead to clusters, combos, or caroms. Figure out when you're going to deal with these from the start, and then work them into the plan. If you know you need to play a 4-8 carom (because the 4 doesn't have a pocket), then figure out what angle you're going to need on the 4 to get the carom and get position on the 4. Then when you're shooting the 3, that's the angle you're looking for. It's really not rocket science.
-Andrew