Point your nose down as far as is safe whilst holding W and not pressing space until your nose goes below the horizon.
Nose down a bit (like 10-20 degrees), press W to accelerate, nose back up 10-20 degrees while hitting afterburner. Zero-to-Fast in no time. EDIT: Oh and spacebar while all that's happening. When you nose down it'll create some upward/forward momentum and allow your engines to "engage" faster when you nose up and hit AB.
AB while gently pulling the nose up is a pretty good answer above. Hover happens when your airplane is not moving forward. Generally pointing your nose in the current direction of travel will transition you into normal flight.
use gravity if you are high enough - turn upside down, V thrust up (toward ground), 1 second later do nose dive, you will reach max speed within seconds after than can do whatever