I used to Solo all the time Hobie 16/14 at Channel Islands in the Pacific and would practice the following drills all the time. When I had a crew, I made them practice with me as well.
Getting confident is very useful.
1.) I Always carried an extra life vest (old but useable) and would toss it overboard and practice searching for it.
2.) I frequently practiced righting my boats in progressively larger seas and heavier winds.
3.) I practiced sailing backwards and had a system of picking up the MO (vest) by backing into it.
I mastered this in calm seas then progressively worked up into scary seas.
No one was ever allowed on my boat without a proper pfd PROPERLY worn.
I also carried the following:
Portable VHF
Whistle on every vest and one on the boat
Sea Anchor
One flare and one smoke
I coil of rope to make temporary standing rigging and help with anything else, lashing etc.