For most players, a trick would be the last option to solve a level. You try all the simple methods to solve the level, either working forward from the starting position or working backwards from the ending position. And you encounter something you can't get past. As a last resort you consider the possible tricks. Probably not the most efficient method.
But if you've seen a particular layout before, it becomes much easier (and you have the rating issue). eg. Challenge-V#0208 (A Series of Tubes). I've tried creating a level like this before (Ch-IV_#0570 - Optical Corner) so I can see what would be required. Btw, my attempt is rated Easy because I tried to make the level Deadly by keeping it very open and this led to a terrible shortcut.
Ratings also depend on what type of level it is and the solver. eg. I would find a Medium level with ice and mirrors easier that a pure sokoban level.
LFE.