Right as a basic starting point this is the sort of to do list that I worked from:
1. Groom (pick one!)
2. Pick a date
3. Pick a ceremony type
4. Pick venue
5. Pick attendants (bridesmaids, best man etc)
5. Draw up a rough guest list so you have an idea of numbers
6. Think about colours/themes/ideas
7. Keep a scrapbook for dress ideas/reception ideas/general ideas
8. Research photographers
9. Research videographers if you want one
10. Think about dresses - use your scrapbook for ideas of that you like in a dress and take that with you for trying on dresses.
11. Make bookings
12. Research wedding cars
13. Look into stationery
14. Start thinking about favours and thank you gifts for important people
15. Pick readings for ceremony (and music if applicable)
16. Wedding cake!!
17. Organise the groom - what's he going to wear?
18. Pick a menu for the wedding banquet
19. Research wedding make up and hair
20. Make sure you have all the relevant paperwork in order!!
That's just a rough guide, there are no doubt things missed off, but as you go along you end up adding extras to the list, merging bits together and then taking things off the list when you change your mind!!