The other two covered most of the Medic tips I could give. The only things that still came to mind...
There are times when it's better to give your life, or at least put it in extra risk. One case was when you were healing me at the beginning of Stage 3 Goldrush on Red. It was earlier in the week, so you might not remember. You popped uber on me early out of reflex, and thought it was a mistake, but it allowed me to block the Heavy/Medic combo from coming up the stairs and wasting their own uber.
Uber can't be used to cap points, but can be used to block. A cart counts as a control point. I like ubering in the last 10 seconds of a round on defense. Even when you go into overtime in KotH, the opponent's team capture will go down while you're blocking it. At other times, it's better to switch weapons and take the uber off so you can quickly cap a final point.
On CTF maps, whoever has the flag can't be ubered. This means that if you activate on them, they won't be invincible, but you will. Or, if you have the flag, you won't be invincible, but they will still. Use this fact when considering who picks up the flag. The 'L' key is the default for dropping the flag so someone else can pick it up.
Remember the sentry example? An uber can be used to block rockets and bullets. By distracting a sentry, one uber can allow five people to jump out and focus it down. Conversely, one uber can stand in front of a sentry and block all fire heading towards it. Alternatively (with some coordination), you can uber the engineer and he picks up the sentry (or tele!) but it means someone or something else has to be around to kill the people who are firing at you.
When it's only you and wartime or something against three people about to cap the final point, it's better to give him the overheal and then die while baiting people away from the cart.
Again on baiting, it's wonderful. It's smart to chase Medics down, but not when it allows the rest of his team to wipe you out immediately. That's why it's better at times for Heavies and Pyros to focus on killing the patients, as those classes can't always escape and/or defend the Medic at the end of an uber.
If you're on an open map like say... Freight at middle point, realize that as you're ubered there will always be some combination of a Spy waiting behind you, a Sniper lining up a shot across the map, a Demoman laying a carpet bomb around you, a Scout/Soldier jumping in on you, and a Pyro/Heavy fresh from sneaking underwater ready to kill you at point blank range. First five seconds of the uber are for picking and taking out targets. The last five seconds are dedicated to getting out of dodge. For every second of those five you don't use to ensure an escape route, your survivability decreases by 15-20%.
Be a coward. The more a team is getting wrecked, the more you desperately have to build an uber, and if you keep following any ol' group of people into a firefight because you want to keep their health up, they will still get you killed repeatedly and you'll be no closer to capping that point.
Finally, and this is very important when playing on random servers and don't feel like using a mic, be mindful of how much ammo your patient has. You don't want to waste an uber or kritz because wartime had 0 of 8 stickies loaded. Still, there are times when you want to uber someone specifically because they're out of ammo, as they're an MVP and saving them from having to respawn would be just as helpful of the team as saving yourself from having to respawn. It can be anything from saving wartime so he can reload and resticky the cart while you stand on it and keep it from moving, or saving an Engineer right after his buildings are destroyed so that he can rebuild much, much faster.
It's almost disturbing that I equate wartime with sticky launcher demomen.
Yeef said:
You've misquoted me.
Anyway, the point is, ubering a sniper when there were literally 2 or 3 direct combat classes right next to us is silly. And Frog isn't a real sniper. He uses the huntsman which only requires you to
sneeze in the general direction someone is in to
hit them. I was using the Bazaar Bargain, which is the weapon real snipers use!
Read: Never ever uber Snipers. Even ubering a Spy is more useful thanks to his revolvers. The only exception to this rule is a Hunstman Sniper, who can then attempt an uber taunt kill ftw.