When I see a really good wave come in, it is pretty obvious. Yet, lots of times I let impatience get the better of me and I don't get the best waves in a session. I'll kick out of a junk wave only to see the really good one I wanted was right behind it. Doh! So again, the quickest way to miss a good wave is to go on a bad one.
So you have to guard against feeling over-optimistic when you see a wave come in. Is it really a good one or are you tricking yourselfself into thinking it is? This doesn't matter too much if you are free surfing and just looking to get some exercise and fun... but if you are competing it is everything. You have to be objective and honest with yourself about the waves' scoring potential... or fun potential for that matter.
As a board maker, there a lot of ideas I consider to help someone improve and have more fun in the surf but its ultimately up to the surfer to pick and catch those winning waves that will allow the surfboard under their feet to really do its thing and feel magic. Better wave selection leads to better surfing, quicker improvement, and more fun!