Originally Posted by zz4gta
There are a lot of things that effect pointing. Usually a boat can point around 45* from the true wind. Those saying they can tack through 60-70* better be on an all out race boat. 30* off the apparent wind is quite common, but true wind is still another 10-15* off that. Lets stick to talking about the angle we tack through, as that is a much better measure of how a boat points.
Some of the things that effect pointing are:
bottom condition and foils
sail condition and cut
zz4gta has it right, but, look at each item on his list. Each item has a direct bearing on boat speed. Anything
that will maximize boat speed will improve a boat's pointing angle. I'll add one item to his list - helmsmanship (i.e., the ability to find the groove, and to keep it there with the least amount of rudder movement).