The framework for a dynamic-static compound set is simple:
A1: Dynamic Exercise, 8-12 reps
A2: Static Hold, to failure
Begin with a 12 RM of any decent dynamic exercise to pre-fatigue the muscles.
Immediately follow it up with a static hold to failure of an exercise that works the same muscles.
Rest 90 seconds. Then repeat twice more, shooting for at least 8 reps on subsequent sets. Three rounds will be plenty if you're legitimately pushing each hold to failure.
Here's how that would look for ab training (reps and hold time abbreviated for demo purposes):
A: Weighted Swiss Ball Crunch or Kettlebell Swing, 8-12 reps
B: Long-Lever Plank (advanced) or Traditional Plank (basic), to failure
Technique Tips
To perform the long-lever plank, position your arms about six inches farther out in front of you than you would for a traditional plank, and narrow the gap between the arms slightly. Pull your elbows in and down (as if to crunch) to engage the lats and abs. Also squeeze your glutes and quads. Your abs should be burning so violently that it's difficult to breathe.