Breathing for Birth
Here are links to videos on various breathing techniques for birth. Review each of them and see what appeals to you most. It's important to practice breathing the last number of weeks of pregnancy so that this comes more naturally when your birthing time begins.
3 Hypnobirthing Breathing Techniques - Even if you are not using the hypnobirthing program specifically, the breathing techniques can be helpful. The section for pushing might be in the middle of the video instead of the end, so the order is off. One tip is to practice the breathing for pushing while you are using the bathroom!