The Medic is arguably the MVP of the Team Fortress 2 crew. Your task is to keep the rest of your team alive, and how effective you are at this job the more your team will love you. Yes you don't get many kills but you still are at the forefront of the fight.

"The medic never heals me, no matter how many times I call."
While a good medic heals all party members, a great medic will prioritize the strongest players and heal them first, also constantly spamming "E" simply will annoy them.
"I keep dying as medic."
This is partialy your fault, medics should:
Hide around corners while their target shoots
Never get too far ahead of meatsheilds, your primary kinda sucks
You're the second fastest class, USE IT. Keep moving and you will outrun enemies, headshots and backstabs.
"I always die with 100% Uber."
When addressing Uber; pop early and often. Nothing is more humiliating than a wasted Uber.

Really this part is not very important, a good medic won't use it much anyway.
Just use the Blutsauger.

There are 4 Mediguns to choose from (excluding skins)
-Stock
Uber grants Invulnerability
Most effective for taking down sentries
Reccommended uber classes prioritized: Soldier, Demo, Heavy if need be (Heavy is terrible at destroying sentries)
In all honesty the stock is the most versitile and adaptable to many situations.
-Kritskreig
Uber grants Critical Hits
Most effective for taking down multiple enemies in oper combat
Reccommended uber classes prioritized: Heavy, Soldier, Demo
MVM strategy
-Use KK 25% faster charge rate and share an uber canteen to excellerate the healing process.
-Quick-fix
Uber grants 300% healing and no movement inpairing
Most effective for getting yourself to the forefront of the battle quick.
Reccommended uber classes prioritized: Soldier, Scout, Demo
Carefull not to abandon the rest of your team simply because you're having too much fun running around and rocket jumping.
-Vaccinator
Honestly, this Medigun is most usefull when either handling enemies one-on-one or handling a team with a majority of one class
No class is very good at this gun, mostly because it sucks and its uber is useless.

Like the primary, your saw should only be used if nessecary, and only if in close proximity to few enemies.
These are not all the melees but they're the ones I deem most effective.
-Ubersaw
Main upside: Fills up Uber quicker with hits.
Downside: Slower swing.
-Amputator
Main upside: Healing taunt allows you to heal your team quicker than one at a time.
Downside: 20% damage reduction
-Bonesaw
Main upside: No Valve nerfs
Downside: No cool effect
Some saw the Solemn Vow is a straight upgrade, except that it can be nerfed and its effect is more detrimental than useful.

DON'T SPEND ALL YOUR TIME UP THE HEAVY'S BUTT THE REST OF THE TEAM NEEDS YOU TOO!