headshotting ppl with scout is so easy once you get the hang of it. First learn how to quick scope, by that i mean, scope then shoot then quickly switch weopons to pistol or knife then back to scout, but it HAS to be done really fast. So scope then less then a second after shoot, then change weapons and get ready for the next shot. Basically do that until your aim is perfect.
Headshotting all you have to do is aim head height all the time. There is a line which runs along where a players head is, keep your mouse at that height (you will know the height once your aim gets good), dont move it up nor down, only side to side when aiming at a person, if you get the feel of always aiming head height you will notice that you constantly get headshots.
Its the same with awps, except you dont have to hit em in the head, but if you practise quickscope with awp and scout, you will find that you have become nearly unstoppable ;)
Keep Practising