I found myself developing my own breathing exercises and the nurses were impressed by them. The important thing is to concentrate on the breathing out, so you don't hyperventilate. I breathed in through my mouth then rhythmically blew out the breath through my mouth in short puffs. (About 10 puffs per breath) It really helped! Also, try to keep mobile for as long as possible to let gravity help. I was made to stay on my back with my first pregnancy because I had suffered a thrombosis in early pregnancy and needed to be monitored. I ended up needing forceps. For the second pregnancy, I made sure I stayed standing and then, in the very last stage, knelt on the bed, leaning over a bean bag I had brought with me. That was brilliant!! The whole experience was so much better!
My daughter had an epidural when she had her baby and now wishes she hadn't because she didn't feel the baby coming out. Gas and air is ok, as long as you don't overdo it. I didn't feel my first baby come out but believe me, there's nothing better than feeling that little being slipping out of you! Thankfully, I felt that the second time and I still remember the feeling! Good luck; I hope all goes well. Be sure to let us know!