Overcoming Gravity recommends the following progression:
- Rings Strap Handstand Pushups
- L-sit / Straddle-L Straight-Arm Press Handstands
- Full Back Level (With Supinated Hands)
- 1/2 Layout / 1 Leg Extended Front Lever
- Rings Advanced Tuck Planche
- Rings Dips (Deep & With Rings Turned Out to 75 Degrees Past Parallel)
For the actual movement itself, if you can't quite hold it yet, Dr. Low recommends training with either a partner to hold your legs, or with elastic bands such as Therabands pushing against your feet. In either case, the load should be managed so that you're exhibiting maximal effort to hold yourself aloft in the cross position.