Originally Posted by the dean
trim to the best glide speed
Not
always a good thing. If your best glide speed is say 60 and the headwind is 40, then you are in a situation where you have fewer fields ahead. In the same wind, if your glide speed is 40, then the only place you are going to is underneath you (unless you can turn around).
It requires some practice to determine optimum speeds to reach a chosen field with differing wind conditions.