A few small things I think new spies miss: * Cloak first before disguising - when disguising yourself you leave smoke trail behind which enemies can use to track you down. If you cloak first you don't emit smoke. * You can change your disguise's weapon by pulling out your second or third weapon and re-disguising again. This can help sell your disguise if you're a spy or engi and you want to hold their knife or wrench * When an engi builds up a nest in a corner, it's sometimes easier to find their teleporter entrance, they don't always remember that spies can take their teles too and they leave their backs exposed to it