Found this over at the Harbour surfboards forum.  Nothing earth shattering but I do like the advice to fade the first turn.  As to "keep your shoulders over your hips" -- I can't figure out what that means.  Anyway, let's start with a photo of David N. from back in the day.  Amazing!

Here is some advice and things I have figured out that have helped me (and pardon me since it sounds like you already know some of this and some is already mentioned-it will just make more sense, at least to me, if I say it all here): 
1) fade the other direction - if the wave allows - before you do your bottom turn and start going to the nose as the board is rising coming out of the bottom turn 
2) take small cross steps are first and don't lift your moving foot completely of the deck - maintain a light touch with deck 
3) bend at the knees and keep your shoulders over your hips 
4) try to noseride when you have a steeper face - not a gentle slope - you will be going faster and like riding a bike, it will be easier to maintain your balance and you will be less likely to stall or pearl - this sounds like your major issue 
5) if you are adventureous, noseride into an oncoming closeout (meaning after you have been riding a while and the wave starts breaking back toward you in front of you). This will make sure the face is steep enough/you are going fast enough that it is very doubtful you will stall/pearl (until you get to the closeout and then if you are quick, you can back up on your board and cutback or at least straighten out). This will give you confidence in critical situations 
6) if the face starts crumbling in front of you (as opposed to a pitching out closeout), don't back off the nose - at least not much - and squat a little so you can maintain your balance (and maybe lean a little toward the face) and grab your rail to not lose your board if you do lose your balance, until you get around the whitewater and standup straighter again. 
7) don't give up! 
Good luck!