There are many different ways to break in a new baseball glove. Some make sense, others are just plain silly. I have broken in several gloves over the years, and even screwed up a couple times. Although, never seriously enough that the glove became useless for play. Here is my philosophy for breaking in a new baseball or softball glove.
Breaking in a new glove requires patience and it may take 1/2 of a playing season or more before the new glove sees game action. I generally use the "new" glove in the outfield while shagging balls during BP, and take ground balls in the infield once I have completed the preliminary "break-in" steps described below:
(1) Unwrap the glove and put it on your hand. Fold the glove across the hinge with your throwing hand several times.
(2) Go out and play catch with the glove each day. Continue flexing the glove across the hinge in between throws while you are playing catch. Have fun and talk with your partner while you build arm strength to play ball, and break in your new glove. If you can find a partner that throws hard, your glove will break in faster and you will get better at playing catch!
(3) If you must use a glove conditioner, use Lexol leather conditioner. It is impossible to use too much. It provides adequate lubrication to the leather fibers, and it does not soak in and make the glove padding heavy.
Put a small amount of Lexol on a clean sponge or rag and rub it into the triangle formed between the base of the web and the hinge at the heel of the glove.
Continue to flex the glove across the hinge while wearing it. This will help the glove conform to the anatomy of "your" hand and give you a custom fit.
(4) Finally, I store all of my gloves on a shelf in the house and use the Glove Guard to help them retain their shape. Of course, a baseball or softball in the pocket also works to keep the glove from becoming a flattened pancake
Do take time and use patience when breaking in a new glove. Don't resort to quick-fix treatments like soaking it in a bucket of water or lubing it up with glove oil and then use a car to back over it in the driveway. Likewise, avoid all of the "Hot-Glove" oven bake methods that essentially cook your glove. These quick-fix methods will shorten the life of your glove or ruin it entirely.
Do remove your glove from the bat or equipment bag following each use, wipe off the dirt and grit, and store it on a shelf with a ball or Glove Guard in the pocket. Don't leave it dirty and stored in the bat bag between seasons and uses.
Do use Lexol leather care products for annual cleaning and periodic conditioning of your glove between seasons, games, and practices.
Use the following procedure to keep your glove in top playing condition.
(a) Use a light brush to remove dust and grit,
(b) Apply a small amount of Lexol leather cleaner with a damp sponge to the glove pocket, fingers, and back to clean the leather,
(c) Use a clean damp sponge to rinse and remove the cleaner from the glove,
(d) Let the glove air dry slowly and apply Lexol leather conditioner to the pocket, fingers and back, rub it in. Store the glove or play catch with it as usual,
(e) tighten the laces in the fingers and web following each season and only use square and overhand knots to tie each of the laces off. Don't use an over abundance of saddle soap to clean your glove (it will make it sticky and gooey forever).
Don't use any of the petrolium based glove conditioners like vaseline. Avoid using oil conditioners like neatsfoot and mink oil, and especially boiled linseed oil. These products will make your glove heavy (glovolium, neatsfoot oil, and mink oil), and sticky so it attracts dirt and grit (vaseline-like products), or ruin the leather by making it hard and brittle (boiled linseed oil). I really believe Lexol leather conditioner is the best product on the market, but other lanolin-based products will also get the job done without ruining the leather in your glove.
Do wear a batting glove under (inside) of the fielding glove during games and practices. This will help keep the inside of the glove palm from getting saturated with body sweat and salts that will dry the leather out over time.
Do let your glove air-dry slowly when it has gotten wet during a game or practice. Don't put it in the oven or microwave, or over a heating vent to speed the drying process. This will cause the leather to crack and become brittle. Be sure to apply a small amount of Lexol leather conditioner to the leather once it has dried to maintain its flexibility.