As a rule of thumb, you will want your arrows to stick out at least 1" past the furthest forward part of your arrow rest when you are at full draw. You do this by very carefully drawing the bow with a full length arrow nocked and having someone very carefully measure and mark the shaft 1" past the furthest foward part of the rest.

On my bow, I have a 29" draw and shoot a 29" arrow but this might not be the case for everyone. Your best bet is to go to a pro shop and have them set you up the first time. Especially have them measure you to determine your own proper draw length. It is money well spent.