When playing a game, hit tab to see your score, kills, deaths, headshots etc.
Playing against scouts can be very annoying sometimes, especially as a soldier, demoman or heavy. Heavy is probably the easiest out of the three classes to kill scouts with, especially if you catch one out in the open. If you can manage to hit a scout with a burst from your minigun you'll usually kill him pretty quickly, especially if he's at close range. Therefore most scouts will try to attack from behind or the sides. Keep your minigun revved up as much as possible and always check your surroundings. If you need the extra mobility, use the shotgun and run back to spawn. Eventually you'll meet another teammate who can help you out. Soldier is probably the next easiest against the scout. At longer ranges just duck behind some cover. Generally a scout will be too quick for you to hit with a rocket. At closer ranges you'll want either the rocket launcher or shotgun, depending on your preference. Using the rocket launcher at close range seems kinda idiotic, but remember that you have more health than the scout and can take the splash damage. A direct hit will either kill the scout completely, or damage him enough that a weak breeze could kill him. According to the wiki, getting to higher ground helps too. Demoman is the worst class to fight scout as. Retreat into a building to force him to follow you and hopefully fall into a stickytrap. Grenade spam is very useful to keep the scout away long enough for help to arrive.
FAKE EDIT: NINJA'D
I usualy play Soildier/Demoman/Heavy.
I usually play on random servers.
My most frequent ones are BigBangGamers(Friend that got me into TF2 and DF community server)
I don't know how to view kill ratio.
Scouts and spies will make me rage quit. Spies with FUCKING FAKE DEATHS ARRGGGGGGG
in particular
Press Tab to view the scoreboard. Your Kills and Deaths, among other things, are at the bottom.
Skilled Scoots are annoying always. If you can stay locked on as a heavy they shouldn't pose much risk, as explosive classes just launch rockets/stickies at the ground between you and hope you can anticipate where they're going. Or use the Soldiers shotty.
Turn around frequently and spycheck anyone on your team until you've seen them attack. Spycheck by running into teammates - spies will bump into you. Always assume spies are Dead Ringing unless you kill them while cloaked, or see them decloak right before you kill them. Viewing the scoreboard can also identify DR's, they won't register as a kill. I don't bother doing that, though. Freak out and flail around shooting whenever you hear the Spy decloak noise. Also, playing DR spy a bit will help you identify their patterns, so I recommend that. I've been backstabbed a lot less frequently since I learned to play spy.
Dead Ringer Spies never drop a weapon either. After you kill a spy, run over its corpse to see if you collect any ammo. If you don't, then it's probably a Dead Ringer Spy. The good news is that you now know he's there. As always, check your back often and shoot any suspicious allies. Hell, shot non-suspicious ones too. Stick close to any confirmed allies too. They'll help with checking your back, and will help intimidate the Spy. That way he'll look for some other guy to attack.
Also:
TF2 Official Wiki's strategy page is your friend.