One of the most important keys you can bind is the "spot" command. Set this to something quick and easy to access because you may only get a split second to "spot" an enemy before they are out of site. If you have been playing the game and heard someone say "incoming enemy light, in the mid field" and a little red triangle highlights on your screen indicating a location on the map. USE THIS to let your team know where the enemy is attacking from, especially if you see incoming cappers from obscure routs.
Built in to all versions of the "Tribes" games there is what's know as the "VGS" menu. This menu sends audio commands to your teammates and in some cases your enemies. It can be used for everything from spamming the word "SHAZBOT!" or for taunting your enemies, but most importantly it is a tool used to give vital information to your team.
Common phrases and combinations experienced people regularly use to let people know specific information like VFF = "I have the flag!" usually means DO NOT take the flag from the stand unless your going for an e-grab OR are going faster then 250 kph, in which case you should be the person spamming VFF.
So here is a list of the VGS menu if you want to print it out;
Later on if you ever join a tribe, this will likely become obsolete as most organized clans / tribes / whatever now a days use VOIP chat programs like Mumble, Ventrilo, or TeamSpeak. But the VGS menu works for public play, for those that know how to use it, and pay attention.