Yes I try to first breathe in and then out! As my need for oxygen increases I try to breathe faster to accomidate my lungs desire to please my heart....Whatever you don ..Don't hold your breathe for too long!
I've been making a concentrated effort on taking a great big breath while I'm in hard braking into a corner. I don't know if its helping or not but there aren't many places on the track when you're not getting fed rocks and dust from any bike in front of you so I figured its the best place to got for a great big gasp. Also unless there's huge breaking bumps I find that I'm not as tensed up so I can probably get a better breath.
my mouth and throat get really dry if i breath through my mouth and its so dry i cant even swallow. i get tired a lot faster from that so i try to breath through my nose, just nice deep slow breaths and if i feel short of breath i'll breath a little faster through a corner or along a straightaway where its smooth and then go back to slower breaths
Try to keep your mouth as close to closed as you can! I found that after about 3 laps on any of the tracks around me, your throat will be coated with dust and breathing will become more and more difficult, breathing through your nose is tough to do for me, so I keep my mouth open like im drinkin thru a straw and that works. Sticking foam from an air filter or something in your mouth guard might work, whoa thats such an awesome idea.
My goggles squeeze my nose making it harder to breath thru it. Some of the guys I race with use those sticky strips that hold your nose open (I can't think of their name right now). I haven't tried them yet but if you are having trouble breathing thru your nose you might give them a try.
whoa that reminds me...my dad wears those so he doesnt snore...i tried one on just to see if it helped and it really opened things up and made it easier to breath, i keep forgetting to wear one while i'm riding though.