MY best class, is, by far the scout, ironically enough. When I get it, I know there's going to be hurt involved. But, and here's the thing, I divide the classes like this: Classes that are available to everyone, classes which are a fuckload of overkill, and classes which are easy to play, and hard to master. The scout falls into the third category for me. At first, I found myself HATING the scout: not a single time I ever tried to run into a base did I ever seem to survive or kill anyone, which drived me insane. But after watching EvilDaedalus' video "How to play the scout", I decided to bench my pride and follow the tippers. And boy, did I like those tippers. Now I pretty much play the scout my own way, but with so many traces of how Daedalus does that you wouldn't care for differences. A few of my tips would be a) NEVER stop moving. For the love of God, that's the only thing the scout is good at. Moving. Stay moving. Don't stop. Oh, and DON'T move randomly. It's what we want you to think. At least, I know I never move around randomly, but I always try to get the enemy's blind spot. b) Like the spy, choose your targets carefully. And even if you don't choose them carefully, at least approach them carefully. I mean, a soldier will always be a hefty choice, but if you take him out intelligently (say, by following him as he enters your fort in 2fort and then giving him a taste of your scattergun close range). This will save you from dying loads, and will also get you kills. c) Know when to retreat. I swear, people have got the "Halo mindset" too embedded nowadays. They take it for granted that you can run fullpelted into enemy strongholds or similar and survive just by sheer determination and trigger happiness. In short, NO NO NO NO NO! The scout is a fragile class. HE even has less life than the medic! So, if you see yourself in a tight situation, or if you already are having the "Oh..." thought, don't let the "...shit" thought have a reason to come out, and RUN TO THE HILLS! Like I said, the scout's main asset is speed and movement. Don't use them to your advantage, and you're not only dooming yourself, you're throwing off board a treasure. d) Help and be helped by teammates. Ok, regardless of how stupid this might sound, the scout isn't and is a team player. He ISN'T because, most times, at the beginning of games, he can run full speed and easily get the first capture, be it flags, capture points or even nuclear warheads (had to finish my rule of three). He can also most times take on ANY other class, and I do mean ANY (edit: except for pyros, they are just the spawn of God's purging fire) class, as long as you keep your wits together and don't run where you can be shot, be it by your objective of by other enemies. The scout has many similarities with the spy in that sense, by that I mean can usually take out vital enemy objectives, such as medics, heavies, demomans (note that the cout can run faster that the demoman can shoot at him), snipers (AND SPECIALLY SNIPERS) and engineers. You just need to wait for the chance. However, he IS a team player in the sense that he will always (like his name indicates) be able to find vital information before others do (sentry locations, spies), and I have yet to play the game in which I don't kick the silly out of an enemy whilst he is distracted with some other guy from my team and I have already flanked him and bonked his head off. e) KNOW YOUR LIMITATIONS. This is not the same as know when to retreat, but similar, howeverit deserves mention. I have many times seen 2 scouts from oppsing teams try to bat the silly out of each other, and I look at them, wondering "Why not just use the scattergun?" so I pull out mine and kill the enemy. But on the contrary, I have seen friendly scouts trying to take out sentries by edging (this is a useful tactic, which consists of shooting sentries just around the edge of a corner) and shooting it with his scattergun. The engineer saw him, and gave him a good taste of lead (of course, the wrench could've been made out of lead, so you never know). What I'm trying to illustrate with this is the following: don't try to do things that the scout's obvious limitations won't let you do. Weapon reach is a horrible problem with him, so try making the conditions favourable to you so that his limitations are decreased to a minimum.
That's all I can think of, really. Hope it helps you guys enjoy the speed and adrenalin rush playing the scout involves!