Jackie Crawford, wrote this excellent article worth sharing:
BREAKAWAY TIP: I thought I would share something that I have been working on myself lately. I feel like I have been letting my horse break a little wide at the rodeos, which has cost me having to go an extra stride or two when the calf steps left. If you feel that you are having this problem or even if not, test yourself in the practice pen. Rake your boxes smooth and then run one and see where your horses feet are landing. If they are not in a straight line to the calfs tracks then you have something to work on. In these pictures I drew the ideal lane that I would want my horse to break in. Notice there is no bow in these lines, you don't want your horse stepping into the chute and then coming out because it is very hard to ride, swing, and have a change in direction. You want one fluid straight line to where if the calf steps left or right your horse is set up to drive of his hindquarters to track left or right. This is going to help you be as close to the calf as possible without breaking the barrier (the red line resembles the plane of the barrier) and be able to set your run up to be fast! Also, test your tracks outside of the box, from about 5ft-10ft outside the box you should only see one set of tracks after you run a calf. If there is a set of calf tracks separately from a set of horse tracks you are not getting behind the calf. Test yourself everyday! Sometimes we can't feel the things that are going wrong, but little things like this can tell us a lot about what is happening!