The first trick to getting your soldier moving faster is the obvious rocket jump. Dating from the old Quake 1 days, it’s really nothing new and will increase your movement speed immensely. When rocket jumping for speed in TF2, remember to jump AND duck at the same time. Ducking provides additional jumping distance and will make you go further with each jump.

The second aspect of getting the most of your rocket jumps is to do them at the correct angle. If you jump too high, you’ll lose speed and range. Jump too low and you’ll move quickly, but only for a limited amount of time. Ideally, you’ll want to rocket jump at a 45-60 degree angle.
View the videos for proper rocket jumping technique.

Advanced Speed for Soldiers in Team Fortress 2!

Now rocket jumping is great, but to truly squeeze all the speed that you can out of your soldier’s jumps, you’ll want to rocket jump off walls instead of the ground. When you rocket jump off a wall, you gain additional speed and range that allows you to achieve distances previously unheard of. The trick is to find good flat walls in each map. Once you have found them, perform a rocket jump off them simply means shooting the wall instead of the ground.

As always, make sure you have a medic to heal you as you rush the middle!