For everybody talking about playing the main I hope they mean with the traveler and not the sheet...

One thing I see with spinakers is the need to anticipate what's about to happen with your sail relative to what the boat is doing, or is about to do. For instance, when you take a puff or you turn up to heat the boat up, the boat is about to accelerate and that will move the apparent wind forward causing the chute to collapse. Anticipating that can make a big difference.

The same thing works the other way - if the boat is slowing down (drop in wind, where you are in a wave, getting ready to heat up), the spin is soon going to be over sheeted. Again, anticipating that can make a big difference.

The telltales can give you a rough idea of where you want to be, but looking at them too much will mean you won't be paying attention to the other things. It also means you;ll be reactive instead of proactive in regards to trim.

On the N-20 we'll get the jib set and leave it, and I'll often use the jib telltales as a guideline (just a guideline) to being on the proper heading to keep the boat moving. Can't often see the spin or the spin telltales, and if things are working as above they would be misleading to me anyway. But that's a two person boat. I call when I'm about to heat up or dig deep to help the crew anticipate.