I don't spend much time in gvs, but here are a couple of observations:
1) If you just full speed towards the enemy base, the chances of a stationary, concealed enemy seeing you and engaging you first is extremely high. It's also quite possible that he has taken a couple of missed shots at you without you realizing it. Advantage: stationary defender
2) Your engine sound gives your direction away to a stationary enemy even when he can't see you. Try this: stop your engine and hop up to the turret MG. Rotate it around. You will hear the sound shift from side to side. Get it in the middle and you know approximately which direction the enemy is coming from.
Advantage: stationary defender
So how do you counter these advantages?
First, just like with airplanes, have a wingman. One moves while the other is stationary watching and listening for enemy. This is called overwatch. The overwatch tank should be able to see any likely positions which can engage his moving wingman as the wingman moves from one positon to the next. The wingman then takes up overwatch.
Second, take advantage of the terrain. Don't crest hills, drive around them. Move quickly from cover to cover, stop, and observe. Shut your engine down often and listen (won't help much if the enemy is already in position, but you might catch him moving up.) Coordinate with those around you to stop and listen at the same time so you know any engine noise is enemy.
Lastly, don't drive straight from the spawn point to the enemy base. That is the most likely avenue of approach and likely the only one the enemy has any defense on. It will cost you time to take a more indirect route, but it will probably get you behind the defending enemy.