According to our very own Robin Walker, original co-creator of Team Fortress, as retold by Nathan Meunier of the Escapist, the Spy’s disguise is nearing the end of it’s lifecycle. And what he said is probably true. Most people now will just melee someone who’s standing there doing nothing. Expect a free crit if you aren’t acting perfectly as a member of the class you’re disguised as would. Nobody’s going to think “Oh good, another Engineer here to help me build!” Or even “Meh. Friendly Pyro.” And don’t think that that Sniper won’t try and put a bullet through your head if he’s not shooting at anyone else.
This is probably something that I don’t mind too much, since I’m a pretty late TF2 player anyway (relatively). Nowadays, the kit won’t fool people for more than a few seconds. Maybe it’s not so useful… but I’ll take any amount of time it buys me.
The point that I’m trying to get to laboriously is not that the disguise kit should be used, but rather, it should be used appropriately. We are given the option of which disguise to use for a reason, and not just so that the enemy starts seeing a pattern every time a Pyro stands around in their base doing nothing. The important thing to do here, is realize when and where which disguise is appropriate. You have a total of 9, and a grand total of 18.
Time to choose, cowboy.
Point #1: Fooling the enemy for a few seconds
This is probably the most basic. It’s only for a moment, but you can use what little time you have to get in and go for the kill. People may not be fooled easily now, but looking like a friendly class is certainly better than running out in the open as a Spy, obviously (plus, of course, protection against sentries). Perhaps you can get that quick stab on that Soldier running past you, or move through the opposing team and cloak before they turn around and start searching frantically.
Where are sticky bomb? Are you really real Demoman?
Disguises that do this well: Pyro, Demoman, Engineer, (except if there are buildings around; you’re a little suspicious without your wrench), and Sniper.
Most do this acceptably well, except the Scout for clear reasons. Medics are a no go either, since they’ll be expecting you to at least latch on to them. The Soldier and Heavy work, but preferably for quick-stabs since they’re slower than any other class, although I do find them handy for running around. Not much difference for the Heavy anyway; out of 100% normal speed, the Soldier is 80% and the Heavy is 77%. That’s a measly 3% folks! Only problem of course, is that a Heavy is a lot more conspicuous than a Soldier.
There are other things, though.
Point #2: Using a shadows disguise
Let’s say you’re hiding in a dark corner or behind a wall the enemy is likely to miss. Or, hiding around a corner waiting for someone to come and get stabbed. You will still need a disguise. Perchance they will turn around and see you, but in that case, might not attack. Not on first glance, at least. And then, once you leave, you’ll already be fully prepped, rather than have a cloud give you away.
Disguises that do this well: Scout, Medic, Spy, and Engineers and Demomen (though less effective for the latter two)
Mrrf mmhmm.
Now, when you’re hiding around a corner, you don’t want that big bad non-existent flamethrower or sniperrifle to give you away to the enemy, do you? In fact, it’s even more likely that they’ll turn the corner and shoot, because they don’t know your team yet, either.
Scouts and Spies are the best disguises here because they’re small, and easy to miss. Their weapons don’t stick out. Same goes for Medics, although their coats are white, making it a little more open.
Use dees! 
Point #3: Stalker disguises
I’m tired of everyone saying that the Medic is a bad disguise simply for the lack of an ubercharge meter. Sure, it’s a bad flaw, but if you zigzag and jump around enough (which incidentally makes you less obvious, since Spies mostly just run straight to a target’s back), they may not catch that less-than-obvious detail. If you’re chasing, say, a Pyro, then it may look like you’re trying to catch up to heal him.
Mediiiic!
Scouts are a bit more obvious, but less people would suspect them than another class like the Pyro. Unless, of course, you’re out for more than 2-3 seconds, in which time you should have already caught the person! What were you thinking?!
Disguises that do this well: Scout, Demoman, Medic
The other classes are less effective. A Pyro trying to run up to a Heavy’s back is pretty darn suspicious, as is a friendly Spy/Engineer/Sniper. But for some weird reason, people suspect Demomen less when I’m disguised as one. I don’t know. Maybe it’s because they’re black, or Scottish, or something. But perhaps it’s because they’re 93% of the regular 100% speed. I don’t know for sure. Regardless, that last speed fact is something that disadvantages you slightly. Hopefully, the guy will run very inefficiently, or stop somewhere to let you catch up.
Point #4: Friendly disguises
Hands up now, those of you who don’t put on an enemy disguise while still in setup/hanging around your teammates. Hands down. You are dismissed. The rest of you, SCHWEINHUNDS!
Most Spies I’ve observed don’t seem to get the idea that disguising as an enemy while in setup/around teammates makes the fact that they’re the much more obvious. I don’t know why, but it seems to happen to most non-career Spies, i.e. those who don’t play it a whole lot, and even then, some who do use the class often fall into that habit. Whatever you do, it’s always better to don a friendly disguise in this situation until you get there.
Himmel, I’ve seen you do it before too. Don’t try to hide it.
I know, I know, that “-” key is hard to reach with your left hand. So here’s what I do. Tap 4, left click, release the mouse for a second to press “-,” and return hand to mouse while picking a disguise simultaneously. This should be no excuse in setup/when you’re around your own/when you’ve just spawned. It’s a quick move, and 98.73% of the time you won’t need mouse control because no enemy is going to be around to attack you.
My favorites for this are Pyro and Demoman. Enemy Spies have a greater tendency to avoid trying backstabs on Pyros, and Demoman is just an all around badass class that no one wants to mess with. Well, not completely true, but it works! And both classes have about 100% speed, so you’ll walk just fine.
There IS an alternative to this when you’re around your teammates, however. See, what I like to do is disguise myself as an enemy Spy. While it’s sad that you can only have the revolver out, it tricks some people into thinking that you’re legitimately trying to score a couple of kills while in this position. You get the benefit of not looking out of place, and already being disguised as an enemy. Most of the time, make sure to switch to a different class when you’re free (often necessary, but not always). Keep in mind, though, that once you cloak out in the open, you glow your own teams color, and that may or may not alert some enemies.
Conclusion
Okay, so we don’t have the best times anymore (unless, if I’ve heard right, you play on the PS3 or Xbox360 =O). It’s not entirely useless, of course, but go ahead and try some of these things out. I do find them to be pretty handy a bunch of times, and of course, if something gives you a couple of seconds more to get closer, then all the better!
Don’t go away thinking “Oh, he’s asking me to use my disguise kit. What an idiot,” because that’s not what I’m saying. The three points I’ve made all support Clank’s Theory of Situational Disguising. We all know the obvious ones; Sniper around Sniper decks, Engy around defensive buildings, Scouts on the cart, etc etc, but here’s an aside from that. Here is, I hope, a guide that will help Spies everywhere to perform just a little better. That is, until the Spy update comes out, fnarr fnarr! (Just in case anyone wonders where that reference is coming from…)
Happy stabbing from,
Secret Agent Clank!
