Stupid Photoshop Tricks (CS5.1)- (not sure if any of the other things I wrote were specific to CS5.1 but I might as well state my version) If you alt+click the visibility icon of one of your layers, you'll hide all the other layers. If you alt+click it again, all the layers that were previously visible will revert to being visible again. Be careful about toggling visibility of layers after doing this hide-all-but-one-layer thing or else you won't be able to revert it. You can Step Backward to before you started messing with other layers, though, and you'll be able to revert as normal. It can be helpful if you're working with a ton of layers, or maybe if you need to sample the color off a layer that's set to a non-normal blending mode.
A while back I was asked to do a quick background mockup for a brawler video game pitch and spent approx 40 hours on this.
I tried to handle it like an actual level and made a bunch of elements (trees, rocks) and pasted them everywhere. EVERYWHERE. I did a few things that would probably be impossible for production like individually shading or editing elements, but since it was a quickie mockup, all's fair.
Daily Sketch Group- Fluffy Dragon in winter
Daily Sketch Group- Orbital view of alien planet
Daily Sketch Group- Worm Wrangler
Not really a sketch, I got carried away with it. Tried to bite off some more of that cartoony-yet-somewhat-ornate Legend of Mana style, found that I had made something that could have been misconstrued as being off-topic, and felt like I had to make explanatory drawings. That's probably a sign of bad design when you need extra drawings to explain what it does, but I think they liked it...