I do not race much any more for a number of reasons but in the day I found a hand bearing compass, a white plastic board and a grease pencil very useful. When laying a mark one can quickly determine whether the angle off the bow is steady or increasing--indicating one is low--or decreasing, indicating one is high and can bear away somewhat. If one is consistantly low but sailing one's optimum apparent wind angle/speed, mark the heading come about and sail the opposit tack until the bearing to the mark is about the last recorded heading. Mark the new heading, tack and repeat. It worked for us.
"It is not so much for its beauty that the sea makes a claim upon men's hearts, as for that subtle something, that quality of air, that emanation from the waves, that so wonderfully renews a weary spirit."