First and foremost, it is not advisable to breed just any Maine Coon Cat. Most good breeders agree that only titled Maine Coon Cat's should be bred, keeping the pedigrees incredibly pure. Breeders also work to breed out certain genetic disorders that are common to the Maine Coon.
Also note that while Maine Coon Cats sell for a fairly hefty price - $600 to $1000 for 12 week old kittens - a lot of money is invested into them as well. For example, you will need to take the kittens to the veterinarian, at least once, before they are sold. You may need to pay for genetic testing as well to make sure that the kittens do not have any problems.
Obviously, you must care for the queens and the studs, ensuring that they maintain good health as well. While there is still a profit to be made, in most cases, you should note that you will not get rich breeding these cats - and you may not make a full time living at it either.
Even if you have titled queens and studs, you aren't ready to jump into breeding. A good breeder will have numerous cat shows under their belts, and they will be highly knowledgeable when it comes to the breed. Current top breeders suggest gleaning as much information as possible and even asking a current top breeder to mentor you - first with shows, and second with breeding.
The worst thing that you can do is to become what is known as a BYB, or Backyard Breeder. These breeders are looked down upon by the top breeders. BYB's commonly don't know enough about the breed, and they often ignore titles. BYB's often do not take the care and caution that top breeders take when it comes to caring for the cats. When all is said and done, most BYB's are forced to sell their kittens at a very low price, and rarely earn much profit, if any.
The environment where the kittens are raised is highly important. These are sociable cats, and therefore, people prefer kittens that have been raised inside of the home, around humans and possibly other pets. This means you need enough room inside of your home for the kittens to roam and play, and to be a part of your life. If you have more than one stud, they often must be kept separate from the females, so that they don't mate with their sisters or mothers.
Before you start breeding Maine Coon Cats, make sure that you talk with another top breeder and get advice from them. Also, make sure that you have joined the appropriate associations, that you have shown Maine Coon Cats, that you have room in your home for the queen, the stud, and a litter of kittens, and that you have considerable knowledge where they are concerned.