Your wedding day is the happiest day of your life; however, it is usually also the most hectic.  Early, detailed planning can greatly cut down unnecessary stress.

The first thing should be to set a budget that you both can agree upon, everything else is dependent on the budget.  Decide on what is most important

and where you then want to allocate the available funds: (is it more important to sacrifice other details of your wedding for the bride's dress of her dreams, or is it more important to have a large reception to celebrate with friends and family).

 
At least six months in advance:
bullet Decide on size and location of wedding
bullet Compile a guest list with addresses (for invitations, etc.)
bullet Send out invitations
bullet Finalize dates, reserve sites (for ceremony & reception)
bullet Hire wedding planner, if desired
bullet Book officiant, caterer, florist, and photographer
bullet Order cake
bullet Plan and book honeymoon

Six to four months:

bullet Arrange wedding day transportation
bullet Confirm reservation of sites, reserve any rental equipment (chairs, tables, etc.)
bullet Register gifts
bullet Purchase wedding rings
bullet Purchase/reserve groom and attendant attire
bullet Book hair and makeup stylists
bullet Purchase gifts for wedding party
bullet Reserve room for wedding night
bullet Reserve accommodations for out of town guests

One to two months:

bullet Obtain marriage license, and request certified copies (link)
bullet Prepare documents for legal name change, if desired
bullet Decide on hairstyle and makeup with stylists
bullet Purchase guestbook, if desired

Two weeks:

bullet Have final dress fitting with shoes, accessories, etc.
bullet Finalize seating plan and write place cards
bullet Notify caterer of guest count

One week:

bullet Pick up dress
bullet Confirm details with caterer, rental agency, etc. of number of guests and meal counts
bullet Confirm honeymoon arrangements, and give itinerary to in-case-of-emergency person
bullet Pack for honeymoon

One day:

bullet Confirm transportation arrangements
bullet Have manicure and pedicure, if desired
bullet Rehearse ceremony
bullet Hold rehearsal dinner, give gifts to wedding party, exchange bride/groom's gifts
bullet Prepare tip and payment envelopes for officiant and vendors, and arrange distribution

Wedding day:

bullet Enjoy your special day, and take in all the memories!