How to break in a baseball mitt?

Oil it very well with a quality leather conditioning oil. Available at harness shops/tack shops/hardware stores. Work it into the leather, rubbing hard enough to get the leather warm to the touch. Now put the glove on and seat a ball just the way you would catch it. In the webbing, in the palm, inbetween, your choice. Now remove the glove with the ball still in place. Stuff both of them down a boot, locking ball and glove together as one. Don't have a boot? How about an old nylon? Wrap it in a good rope. Anything non-sticky to lock that ball in place. Put it in a moderately warm spot NOT HOT(next to a radiator/stove/under your electric blanket) out of the sun, for 12 - 24 hours. Take it out and play catch with it. How does it feel? If not perfect, do it all again.