One of the best ways to climb the learning curve quickly is to go lawn sailing before you hit the water. You can practice and make common mistakes w/o getting wet and running over the spinnaker. If you have spectaters let them hold the boat down if it wants to scoot along the grass. If the wind is lighter then just your weight on the boat will suffice. We have sometimes gone trailer sailing but clear the parking lot first! Better to put the boat on the grass and secure it whatever way is best for you.
You can make big mistakes this way and then get out of the boat and check it out very quickly and easily. Did a big lump keep the spinnaker from going into the snuffer? Walk over and see why as you hand snuff it. Did the spinnaker fall down in front of the hull before it went into the snuffer? If so, on the water that would have been a shrimping experience and probably would have ripped the spinnaker and maybe caused a capsize. You can practice different methods of launching and retrieval on the lawn till it looks good and seems to work well before adding the complexity of water. With a new crew you can quickly develop timing and coordination.
By yourself: You want the spinnaker to go up and come down as quickly as possible so that means using both hands and arms swinging through big arcs to get the halyard up or down fast. You can steer with whatever body part works best for you in the given conditions. In lighter air and/or smoother water, I often stand up (bent over) and hoist while steering with one leg against the tiller connecter. If it is a little rougher I will just kneel and steer with my butt or back leg against the bar. I need only about 5 - 10 seconds to do this and I count the number of pulls I make so that I know when it is there which is what you can do when you practice.
A very common newbie mistake is to bear off on the takedown and let the spinnaker sheet go before snuffing. This allows the spinnaker to get in front of the hull and then run over before you can get it sucked into the snuffer and/or the sheet gets inside the leeward hull, sometimes to the point that it gets wrapped around the rudder. This is always a lot of fun to straighten out by yourself on the water especially if it is breezy and bouncy. At least it is fun for any spectators! You can avoid this by keeping something on the sheet like a leg cleat, foot cleat, butt cleat, etc. You ease off once the sail is in the snuffer and the sheet is prventing further progress.
If you capsize then it is important to snuff the spinnaker any way you want before trying to right the boat. A wet spinnaker at the top of the mast will resist nearly any righting force, even a buoy tender at full throttle if the cat and kite is big enough (another thread).
The common newbie trimming mistake is to undersheet the spinnaker and sail too deep and slow. Trim it out till the luff breaks and then sheet it back in just enough to pull the fold out of the luff and then head up a little until the luff folds over again and then repeat until you are going as fast as you want or can handle. Feel free to move the helm a lot as once you get good at this with that size boat you can just cleat the sheet and sail just by steering unless it is very puffy and/or shifty. Normally it is fastest and most interesting to sheet some and steer some in a coordinated way which tiller time will make clear. The payoff is one of the most enjoyable cat sailing treats; flying a hull off the wind under spinnaker.
You should be good enough by the end of the season that you will have new neural pathways developed that make thinking nearly unnecessary while doing this!
