These timings are just a guideline we would, however suggest that you do not leave things any later than this.

6-12 Months before the big day

Decide on a date.
Make an appointment with Clergyman / Officiate.
Determine a budget.
Compose a guest list.
Set time, location of Ceremony, Rehearsal & Reception Venue.
Choose Professional Photographer / Videographer.
Shop for wedding gown: Several fittings will be required.
Obtain estimates for Floral & Music; book services if possible.
Register with gift registry.
Select brides maids.
Pick a honeymoon destination: (Check passports & inoculations.)
Begin selection of a Caterer.
Set a date with bridesmaids order dresses.

5 Months before the big day

Finalise guest lists.
Order invitations & announcements.
Order personal stationary & thank you notes.
Plan reception.
Choose florist.
Men choose attire.
Make honeymoon reservations.
Choose caterer.
Confirm delivery of bridal gown.
Make appointment for portrait.
Order wedding cake.
Arrange transportation for the bridal party to & from ceremony/reception.
Go over details of reception with caterer / hotel manager.
If you are renting any equipment, reserve now.

2 Months before the big day

Inform clergyman of all the details of your ceremony.
Keep a gift diary - send thank you notes either as gifts arrive OR more traditionally when you return from honeymoon.
Fine tune guest list.
Plan rehearsal dinner.
Select attendants' gifts, grooms gift.
Check all services.
Make moving arrangements.
Final gown fitting.
Bridal portrait sitting.

1 Month before the big day

Choose wedding rings.
Mail both Wedding Day & Evening invitations,
Keep a list of acceptance and refusals as they arrive
Check with caterer / reception venue with last minute changes.
Finalise seating plans, place cards.

1 week before the big day