I had a very quick active labor, 1cm to 10cm to baby born in 1.5 hrs (versus 2 days my first time!) so I didn't have time to pull out all my tricks, but I found incredible relief standing in the shower swaying my hips when contractions were getting harder to breathe through. Sitting on my exercise ball in the shower was great too. If you don't already have an exercise ball, get one. It helped so much!
One thing I didn't so much care for was the baby pool; I didn't like not being able to move as much in there.
Early on holding an ice pack to my lower back was the best. During transition I needed tons of counterpressure; we used tennis balls pressed against my lower back til the contraction passed. (tennis balls stuffed in socks roll better).
Make sure you have everything handy in one place so whoever is helping you doesn't have to hunt. When active labor kicked in for me it came on like a freight train and my fiance didn't even have time to go down the hall for anything before we knew what was happening, I needed him RIGHT THERE
Mentally, I had made lots of notecards with affirmations to repeat in my mind. The shorter the better, as I didn't have time for long thoughts. One I kept repeating was, My baby is coming. It helped take the focus off the discomfort and reminded my of why I was going through all this work in the first place. And then I got into this mindless chant of "Ok, Ok, Ok..." through transition, and for some reason that helped too.
I don't know if reflexology worked for me or if it was just a good distraction, but I also held two small combs in my palm and squeezed the teeth into my palm (beneath the fingers where you get calluses). Easy to do and it seemed to take some of the edge off.
I asked my midwife to tell me something good when it was getting tough and she told me everything was going perfect, my body was big enough and there was plenty of room for my baby to come through. Of all the things she said, this one stuck the most and made me instantly relax. It reminded me that everything I was feeling was normal and necessary to bring my baby out, and it all started to feel so perfect.
I guess the most important thing is to have faith in yourself and your baby and keep all negative thoughts out and your muscles relaxed. Your body will do this, you just need to cooperate!