After playing with this stuff over the last few months, I have some simple pointers to pass on:

  1. Test your comms and interfaces before you build the robot. Its a lot easier to test if the wheels turn or not when it doesnt want to launch of the table.
  2. Know where the center of the servo motors are before you put things together.
  3. Wheels are easier to configure then tracks, but tracks provide better turning options.
  4. Read the documentation well before you launch into things, sometimes with hardware there is no undo.