Wedding Prep Timeline

Wedding Wire has a good checklist, right here on this website. Most of the other ones do to, like The Knot, Zola, etc.

You can also just google "wedding planning checklist" and come up with others.

WeddingWire has a checklist.

Just keep in mind though that it needs to be adjusted accordingly to whatever amount of time you have left and that you don't have to do those things in that order.

If you know where you want your cake from. I'd suggest talking to that bakery and asking them. In case they only do X number of weddings per week. (We're doing Sam's Club and were told no more than 2 weeks in advance. But other normal (smaller, more exclusive bakeries) probably need much more time.
Bridesmaids - 6 months at the latest
Groomsmen - 3 months
Registry - we went when we had some free time. A little over the year before the wedding. We know we will have to make changes, but the basics are there.
Save the Dates - whenever. Some people do a year, I'm doing 8/9 months out. Probably wouldn't bother after 6 months out.
Invitations - roughly 8-12 weeks ahead of the wedding.

We booked our baker 6 months out, finalize our dessert order 2 weeks out.

Bridesmaids bought their dresses as early as 10 months out, or as late as 3 months out.

Groomsmen reserved their suits 1-2 months out.

We sent save the dates 10 months out, invites 3 months out, RSVP date 40 days out.

We did our registry online (Amazon) and worked on it all year long.