Announce your intention to marry to BOTH sets of parents. Arrange to have them meet if they haven't already.
Determine type (formal, semi-formal, informal), style and theme of the wedding.
Make a list of what is important to you for your wedding; this will help you determine your budget.
Sit down with your fiance and ALL parents and discuss the wedding budget, and who will pay for what.
Choose and purchase your wedding rings.
If you haven't already finalize and purchase your wedding gown, veil, and accessories.
Finalize music selections for the ceremony and reception and turn them in to the DJ/Band/etc.
Finish (and print) the wedding program.
Finalize wedding vows
Confirm all final payment amounts with your vendors as well as date, time, etc.
Layout everything you need for the next day in a safe place (marriage license, dress, shoes, etc.).