@skienbaum: A big part of it isn't just planning out lines, but sort of flowing through the level more naturally. Start working on what types of tricks take you through certain types of environments. Learn where a wall ride, a wall plant, a manual, and a grind work, and then start putting those together. Warehouse is a good place to knock out some simple combos. If you're looking for higher scores, goose those numbers by earning your special with a few easy manual tricks, and then beginning a new combo starting with some special vert tricks. The biggest points are going to be in that stuff. If you can start a combo off with a 900 and a revert, then go into a manual, you're well on your way to beating the combo challenge in any level. You pick your starting spot where you think you can net big numbers, and then let your momentum take you where it does.