Always work from the outside to the inside on the perimeter to avoid large shifting of gems. This will prevent cascades, which will cost time to recover from. Do not go out of your way for clock matches. Try to incorporate them into shifts that you have to do anyway to get the target pieces you need in place. Start grouping clocks in the same general area and they will match on their own without you taking extra time to align them. Always look at the next color gem so you do not have to waste time scanning for its location.
Puzzle Quest: Galactrix