Getting married is not all ball & chains. There's a lot of hard work to do before taking the dive. Planning a wedding is no small feat and while you may find out (if you have not already) that although virtually none of the decisions are yours, you still have to do almost half the work. Consider it like owning a 49% interest in your fiance's company.
All joking aside, while there are no hard and fast rules to who-does-what when it comes to weddings there are traditions that are somewhat entrenched. The bride is usually responsible for everything that involves the "look" or "theme" of the wedding (wedding reception hall, flowers, wedding invitations, wedding photographer, etc) and very little else. Believe me, those decisions will take her unfathomable amounts of time. I know you're thinking, "How long could it take to pick an invitation out of a book?" but trust me, just let it slide.
Most often, the groom is responsible for:
* Your side of the guest list
* Marriage License
* Blood Tests (if required)
* Limos for the Bridal Party
* DJ or Band
* Rehearsal Dinner Toast
* Best Man / Groomsmen Gifts
* Wedding Night Hotel Room (if the Honeymoon does not start right away)
Schedule the marriage license and blood tests as soon as you can with your fiance (you both have to be there). Since this does require both of you, do this before anything else to get it out of the way before things start to get hectic.
Discuss everything with your fiance and make sure you're both clear on who is responsible for what. You just might impress her by knowing what you've got to do before she does and being proactive. Then again, she might expect this is all common knowledge and act like you're mentally deficient. Women.
Once everything is settled it's time to get to work. Get everything on your list checked off well in advance of the wedding date. You do not want anything hanging over you in the final run up to the wedding and considering how much stress everyone else will be under your best move is to stand ready to put out political fires from inter and intra-family conflicts as they arise.
May you have the best of luck, because you are most certainly going to need every bit of it!