1) Any reasonable ring strength series - This series should include a press variation (either to shoulder stand or handstand), a support variation and some kind of lever at the very least. Click here for an example of a basic ring strength series.
2) Press handstands - Any variation is fine, although for the most benefit, the emphasis should be on developing the ability to press from either an L-seat or straddle L.
3) HSPUs - Try to build to a full range of motion on these; hands to shoulders on either parallets or rings. Free balancing is much more beneficial than supported. Advanced trainees can, and should, substitute chest roll variations or Bowers in place of the HSPUs.
4) Rope Climb - Legs in a straddle L position
5) Front & Back Limbers - Done correctly, these are excellent for developing core strength and flexibility at the same time. Wall walks are an excellent starting point for these skills.
Yours in Fitness,
Coach Sommer