The ring dip is a very demanding movement. It takes strength and stability in both the shoulders and core. A ring dip will transfer into other movements you see in the gym such as a push-up, a burpee, the bench press, and muscle-ups. Find the progression that fits your ability and work your way up as you gain the strength and stability. Once you're able to master the basics, it's easy to advance as the fundamentals don't change. Strength and stability will be the deciding factors as to how fast you advance through the progressions.
1. The Push-up
Start with the strength of the shoulders through the push-up. Keep the elbows tight to the body. This will help as you progress into the dip. When you can perform 3-5 unassisted push-ups, progress to the next step.
2. The Box Dip
Let's try to keep the hands neutral with this one. Use a pair of dumbbells on the box to mimic a pair of rings. With the feet in front of the body, lower your shoulders to the hands until the front of your shoulders get below your elbows. Keep the elbows close to the body and don't let them flair out. Return to full extension of the arms. After mastering the box, progress to the rings.
3. Feet on Ground
Set your feet just in front of the body with your arms at full extension (the hollow body position). Lower your shoulders keeping your elbows tight to the body. When the front of your shoulder touches the ring, return to full extension. Be careful when performing these that your hands don't get behind the body putting your shoulders in a bad position. Watch the video for a demonstration for what I'm talking about. The best way to fix this is to think about keeping your hands on the body at all times as your chest drops to get your shoulders to the rings.
4. Feet on Box, Knees Bent
Similar to feet on the ground, place a small box or a few plates just in front of the body. Here, you can assist the body as needed with the legs to help push you to full extension. Don't overuse them though! We don't want to make it too easy!
5. Feet on Box, Legs Straight
This one is way more difficult as it demands a lot of strength as your legs are raised and straight. You are unable to use the legs as much as you would with them bent.
6. Strict Ring Dip
Maintain the hollow body and the stable midline. Don't let the feet come behind the body. You're feet aren't anchored anymore, so make sure to keep the elbows tight to the body!
7. The Kipping Ring Dip
The kip allows for faster reps with less energy spent. When you're in the bottom of the dip (with the feet in front - hollow position), do a very quick knees to chest and immediately back into the hollow position.