start playing with it regularly; be patient, work warm-ups in the wrist + get comfy being upside down, get good at falling out and catch yourself (cuz you're gonna fall a lot!)

The most common problem I see (in handstands and other arm balances) is that people don't get their center of gravity sufficiently above themselves; in handstands your hips need to be above your shoulders and above your wrists. = if misaligned (not far enough up, or too far) you're gonna fall that way.