If you want to keep things at the most basic level, consider that, more often than not, what paid on the first lap will pay again on the second lap. If you go with this mindset, you will do well most of the time, but if you want to be correct more often, (and you need to be if you want to win) you should take it a step further and accurately identify “why” something paid on the first beat and use that knowledge to sail a smarter second lap. Sail the long tack, or head to the racecourse feature that paid on the first beat.
The best tacticians in the world are incredibly observant and you should be, too. During the first lap, in addition to observing what happens to you by watching your compass and feeling the wind, keep your head out of the boat and notice what happens to others. Boats spread out across the racecourse are extremely helpful in figuring out shifts and breeze strength, as well as gains and losses from current. As boats come back together toward the top of the course, it’s easy to see gains and losses. Having an idea of who went where and how they did really helps decipher the course. As the run develops, you should be observing as well. Is the same side of the racecourse paying on the run or are opposite sides paying?