Scout is a very versatile fast paced class also a heavy damage dealer making it both an exellent support and solo class , Low health and only hitscan weapons means timing and good accuracy are critical.

The scouts main function varies throughout the game, typically on control point maps the scouts would be expected to arrive at the middle control point at the same time as the demoman giving him support and protecting him from other scouts. As the game progresses the scouts role changes typically the scouts are expected to cap the control points as the heavier classes push forward, this seems contrary to what most people would think they should be doing, less experienced players will attempt to use the scouts speed to attempt to push on by themselves, however this is detramental to the rest of the team, as the scouts cap faster than other classes (x2) it is more effective that both scouts stay on the control points while the heavier classes with their reduced speed push forward, as the scouts then push forward this allows the entire team to remain as a single unit for attacking the next control point.

Typically scouts in any 1v1 situation are likely to come out on top due to their immense damage and speed, however in a 6v6 situation the scouts must attempt to focus their attention on critical targets (medic, demoman, other scouts) as the bulk of the enemy team combined with the medic heals will make it almost impossible for them to simply kill everything solo, engagement must be done cautiously and the scouts must focus primarily on staying alive to help support the rest of the team and capture the control points as the rest of the team advances.
Other things to think about as scout are 1v1 / 2v1 / 3v1 combat situations vs other classes, it is perfectly possible for a single scout to kill a medic attached to either a demoman or a soldier solo, however typically a scout vs 2 other scouts will rarely prevail, scouts vs specialist classes should also approach combat situations with caution, a scout vs a pyro should be typically fought at as far a distance as possible, using the pistol to weaken the enemy pyro before finishing him off with a few scattergun shots, similarly a scout or 2 scouts vs an engineer the focus should be on killing the engineer himself before taking out the dispenser and sentry gun with the pistol, however this is not always possible and if a sentry is in a good position (where the scout cannot either strafe around or jump on top of to avoid the sentry locking onto the target) then the best option is to retreat to support the rest of the team.

Aim practice, aim is critical for the scout practice regularly and stay on form the extra 5% accuracy from being sharp may be the difference between winning and losing a game. Think of the rest of the team, its easy for a scout to forget about the rest of the team due to the speed and firepower the class has, if u can focus on helping the team with these attributes then victory will become easier.