This is just some things I've picked up on building bots. Nothing special really, but it makes it easier in the long run...

• Study the circuit before you start building. Make sure you understand what it does and why it does it.
• If you are freeforming, draw a diagram with all the connections between pins and components. I usually do this with IC:s in the "dead-bug" fasion, with the pins facing up. I don't want to remember the times I've soldered a component in place, just to discover it's not where it's supposed to be because I've made a mistake on what pin I'm actually supposed to use...
• Before you start soldering, take some time to figure out where to put everything. This helps to keep the freeformed circuit compact and tidy.
• Always check the pin-configuration on transistors. Preferably before you solder them in...
• Take your time to make your bots visually pleasing. What looks good to the eye often functions well, too. Oh, there's something about that A in BEAM as well, something I seem to have forgotten most of the time if you look at my bots...
• If you build your bots reasonably small and light-weight, aluminium from cans make good structural reinforcement. You can choose to use the colored outside of the can if you want to, but I usually use the clean metal inside of the can.
• Build as your bots as light-weight as possible. Less mass means less torque to move means lower operational voltage means quicker movement and the ability to move in less light...