As we near the end of the class guide we come to what I feel is the most versatile and deceptively hard classes to play in the game. The second heaviest class in the game, the soldier is equally at home on offense and on defense, and on any team it should be the class in greatest abundance.
You are actually firing landmines
Aim at the feet of enemies whenever possible, its much easier to catch people with partial splash damage than it is to actually hit them dead on with rockets. Not even the best TF2 players can reliably hit enemies dead on with rockets.
Whore the quickswitch
You have a shotgun, use it! I can't count the number of times I've seen soldiers trying to reload their rocket launchers mid fight, quick switch to the shotgun as soon as you run out and use it instead. The shotgun is also useful at longer ranges or when firing at angles where your rockets won't hit their feet.
More than one kind of rocket jump
I'm sure everyone is familiar with the normal rocket jump that has a high arc and can get you to the top of 2fort or the last cap in Gravelpit, but there is also the rocket run. The run is useful in getting away with a flag more quickly or rushing out to defend a point to get to one before the timer runs out. To perform this jump, do a 180, point the rocket launcher at a more shallow angle than you would with a normal jump, and fire while jumping. This will launch you at a more shallow trajectory, but you will jump a greater distance.
Long reloads are long
The rocket launcher and shotgun have two of the longest reloads in the game, whenever you are not firing you should be reloading. Hold down that reload button at all times that you are not firing your weapon. If you run out of ammo for both weapons, fall back, as you have a much slower reload time than any other class.
Mind the delay
Double meaning here, there is a delay between when you press mouse1 to fire and when the rocket actually leaves the launcher, and from when the rocket leaves the launcher to the time it takes to hit its target. All of these factors must be taken into account when using the launcher. It all comes naturally with time and practice, just be ready to miss a lot when first playing soldier.
Relating back to firing land mines, if you score a direct hit on players feet, it will bounce all classes (minus the heavy) around. While in mid air they are at a pretty extreme disadvantage, being disoriented and unable to properly aim. After they are in the air you can either quick switch to the shotgun and drop them while they are still in the air like a clay bird in skeet shooting, or predict where they are going to land an hit them with a second rocket as they hit the ground.
Everyone should be at least mediocre with soldier before they move on to master other classes. Being skilled with the soldier allows you to give your team an out in almost any situation.
Losing on D?
Switch to soldier
Switch to soldier
While the soldier is the most versatile and well rounded class, don't overdue it if your team already has 3 - 4 of them.
If you haven't already, please check out the other parts of the class guide...
Scout Pyro Demoman Engineer Medic Sniper Spy