[AustinSchuh]

One skill that I always find useful is being able to express a design wholly in a single sketch, in order to test it out without spending the extra time to actually model it all up.

With that being said, try designing a pneumatic claw. I'd start by drawing up the basic design in a sketch, and once I had worked out all the details, then using what I learned from my sketch to make all the parts. One of the more fun designs I made in 2007 was a pneumatic claw that also had two pistons to rotate the claw 90 degrees to the left and to the right.

Things like 4 bar linkages are fun to try to design. It's easiest to design them first in a sketch, and then make the parts for real.

If you use sheet metal, another fun trick that my brother taught me is that you can model up something using the thickness of paper as the sheet metal thickness, print it out at full scale, cut it out, bend it along the lines, and then glue it together. You can test all sorts of intricate sheet metal creations that way.

Good luck!