Typically, high tier teams will power coat their robot. This colors the metal on the robot so it looks a lot cooler (see 1114, 254, etc.). However, these teams typically have a sponsor willing to do it for them, as doing it at home is VERY dangerous. This also required parts to be done long enough in advance to get them powder coated.
148, The RoboWranglers, in addition to powder coating, have red lights in their robot. This provides a cool effect, but not in really bright settings. Lights can be a great way of adding effect. In 2011, teams 111, 1501, 217, and my own team, 1126, used lights on their robots. 111, 1501 and 1126 used an LED strip on part of their robot, both flashing and with a solid color. I'm not sure what exactly 217 had, but their arm had a lightning bolt cut into it, with green light underneath. Seeing that up close, it was SICK!!
Side panels on a robot can add a lot of aesthetic appeal. On 1126, we have blue polycarbonate (I believe) side panels, on which we imprint our team numbers, sponsor logos, and other cool stickers (we had a Darth Vader sticker that read "Who's your daddy?"
). In addition, we have these panels hinge on the base of our robot, thumb screw it into the frame, and we attach our electronics to the panel. Then, we just unscrew it, and we have a convenient access point for electronic checks.
I hope this helps!
Feel free to ask if you need any help
-Leeland