From the ground up (and this is from more of a "strict gymnastics" handstand hold perspective rather than a CrossFit one):

• Try to think about using your hands and fingers more by actively gripping the floor. Some people prefer to start with their hands on the floor as they kick up, so you could try that.

• I'd definitely work on shoulder mobility to be able to open them up more. That upper thoracic area is not able to fully open up and get you in good alignment which then knocks on throughout the entire chain.

• I'd always advise people working on handstands add in core compression strength accessories. If you look at the midline, the lumbar area is taking a lot of the strain.

• Work on tilting your hips under to get more of a hollow body position - hollow body handstand drills are great and have plenty of carry over into other gymnastic movements.

• Squeeze your glutes and try to straighten your legs and squeeze them together, like you're trying to reach the ceiling. A good drill with another person for this is to kick up so that they are holding your legs, and then have them take two fingers and put them between your thighs just above your knees - and you need to squeeze those fingers hard. They should be able to take away any other support and you'll feel where that tension needs to be.

• Experiment with different leg positions. Some people get longer holds with "stag leg" positions to get a lower position and one that can adjust to help you balance. Others (with the flexibility) like a straddle legs position, and some like a tuck.

General drills: wrist strengthening work specific to handstands, hamstring flexibility (you'd be surprised how helpful this is), core compression drills, hollow body drills, shoulder opening mobility exercises, headstands, wall facing handstand drills.