12 - 16 Months before the wedding

Choose a wedding date.  Don't rush.  Give yourself enough time.  The best way to do this is to visit ceremony and reception facilities at which you would like to be married and have your reception.  Choose a date based on availability.  If you give yourself a year or more to plan, you have a much greater chance of booking your desired venue on your desired date.

Start a wedding file.  This is a file or folder to keep all your wedding documents, contracts etc...  Organization is the key to staying sane during the planning phase.

Discuss & Choose the style and formality of your wedding.  Pick what best suits your lifestyle, personalities and budget.  "Formal",  "Semi-Formal" or "Informal".  There is no wrong choice.  This is your day and you should make it your own.  This will also help in narrowing down which venues you will consider.
 
Put an announcement of your recent engagement in the local paper.  This is optional, but is a nice touch and memento.
 
Decide on a wedding budget.  Common sense dictates that you do not spend beyond your means.  The last thing you want is to begin your marriage in major debt because of your wedding.
 
Hire a wedding consultant if you plan to.  Some brides choose to hire a wedding consultant to ease the stress of planning or because their schedule doesn't allow enough time for planning.

Select a ceremony location.  Keep in mind that reservations are sometimes booked over a year in advance, so if you find one that you like, put a security deposit down to hold the date.  Always check the cancellation/refund policies first and have them in writing).

Select a reception site.  Many times the ceremony and reception will be held in the same facility.  If this is not the case, be sure that the ceremony and reception facilities are available on the same date.  also keeping in mind that they sometimes book over a year in advance.  Again, always check the cancellation/refund policies first and have them in writing.

Start shopping for a wedding gown.  Custom gowns can take up to a year to prepare.  Be sure to begin this process as early as possible.  Sometimes the wedding gown can become a stress factor, so the more time you leave for this, the better.  Keep in mind that alterations and final dress fittings can also eat up extra time. There are no refunds on wedding gown purchases, so make sure your selection is 100% what you want.  You can also start looking for a coordinating veil and tiara.