Question: My pedal tones suck. How do I fix that?

Answer: Pedal tones are kind of weird if I can't show you or hear you doing it.  First off, your initial (and I guarantee you will do this first off) reaction is to blow less air, because you will try to finesse them into being.   Unfortunately, pedal tones only come out if:
1)  You are using a LOT of air.
2)  You kind of drop your lower jaw a bit (mine kind of juts out) and play in a more upward stream of air.  
3)  You open up your throat and the inside of your mouth by dropping your tongue.  

You will find it difficult to do find actual notes in the pedal range at first.  To start with, you may only get lame farting noises, but push that air and you may be able to pull the pitch up into a real pedal note.  The pedal C and the pedal F (right below your low F#) are the hardest notes to hit in the first pedal range.   You may want to start with D's and Eb's, cuz they're the easiest, but learn to expand it and find all of them from pedal F to double pedal F.  Pedal C is a tricky one.  It is the fundamental partial of the trumpet's harmonic series.  This fundamental should be a slot for you to just fit right in tune, buuuuttt....it's not.   The fundamental C is actually about a minor 3rd low (an A).  So you have to keep firm corners and speed up your air, and make it go sharp enough to be a C.  But all that is if you want to do it open fingered.  I suggest that way.  But, some people are pansies about it and just learn to play pedal C's 1-2-3, which is much easier but doesn't sound as good or do as much for your playing.  And for those of you out there that want to have a range like...oh, say....Byron, these pedal tones certainly did a heck of a lot to get his high register where it is today. Think about that.
-Joe
Joe@TrumpetBoredom.com