Pete,

Sounds like you are looking for the obvious. Most of time sailing is about playing trends and not having some huge literal sign telling you to go. Watch where you are sailing on each tack every lap and compare it to the previous times. In a race like Tradewinds there are boats everywhere, be very aware about who went which way and how they did, this will tell you loads about favored sides.

As Dan pointed out you realy need to be honest about your relative boat speed. If you can not make the start and have equal if not better boat speed than everyone else, upwind and down, then all the course reading tips in the world will not help one bit.