The most important thing to point out to a new medic is this: When defending a base there are some people in some places you shouldn't attempt to heal. Veterans among you will already be murmuring 'bloody snipers!' and this is very true. The last thing a sniper wants when he is strafing along through the sniper-nest is a medic obstructing his way and causing him to be picked off by enemy snipers. The same goes for engineers if they are standing by their sentry guns. If an enemy enters the surroundings and you are obstructing the sgun, then you and the engineer will both be distributing your body parts over a large area while he finished of the gun, and makes off with your flag!

Medics can act as spy detectors by telling your team mates to stop when approaching the flag and letting them heal you. If a spy walks through and he sees that you are looking for him he will try and copy what the rest of your team are doing. Hit him with your axe and he will be infected and will not get far.

You should heal the flag defenders and help them collect ammo. Because the medic does not use rockets or cells you can discard your ammo and give your team mates that bit of extra help.

The supernailgun should be used as a defensive weapon over the bioweapon because you don't stand a chance against a rocket when you have the axe out. You can usually kill the attackers but you will need help to finish them off. A medic and a sentry gun will usually make the enemies life all that bit harder.

Use concusion grenades freely, they are sometimes your only means to kill the enemy... you will stand a much greater chance of fragging that enemy hwguy if they cant see straight won't you? So don't be afraid of using them.

Your normal hand grenades are an excellent weapon. You should be able to bring the most heavily armored of your enemies to their knees if you grenade them befor you shoot them. Use grenades if you are being chased or are wanting to split up your enemies.