Don't Really Listen to What Wedding Planning Books Say
Every wedding planning book has a suggested budget percentage wise. You can follow these but it probably won't fit your wedding. Remember that these planner and wedding magazine companies probably work with vendors and want you to spend TONS on your wedding. So there is plenty of reason to take their suggestions with a grain of salt. For example we looked at one that said something like 5% for transportation but we had our wedding and reception in the same place, we didn't really need a limo or a horse drawn carriage. So how do you set your budget?
Decide on Your Four Walls
When talking about personal finance Dave Ramsey talks about the "four walls" being food, transportation, shelter, and clothing. Obviously things are a little different with wedding budgeting but decide what is most important to you or rank everything. We picked photographer, reception DJ, venue and my dress as the most important things.
Find Out What the Important Things Cost
For the most important things, I would just see what it would cost from vendors around your area to get what you want. I would still go with the least expensive that seems to do what you want. Having a good reception DJ was important to us, but our guy was great and cost $550 instead of the almost $1000 that other places were charging. After you've gotten the most important things on your list look at what you have left and make it work. Side note: every vendor is likely to say that their piece of the wedding is the most important part because they do that for a living, and this isn't to say that they're just trying to sell a product. They decided to do whatever 40+ hours a week, when they got married (if they are married) they probably cared about what they sell the most. Let vendors that don't have a standard fees know that you have a certain budget, they will honor that budget. Good vendors will see that as a "make it under this" threshold.
DIY what you can
I have seen weddings with DIY everything. People have had weddings at their house or a family member's house, TONS of people DIY decorations or invitations, and people have just relied on guests' pictures for their photography. Eric and I got invitations from Vistaprint (WAY cheaper, and in my opinion, same quality) had Eric's mom make most of the decorations and had a friend do make up and hair. We didn't really care to spend a lot of money on those things. Just remember you want to talk about how fun it was and not how much you saved. Doing some things yourself or relying on family members can make that more realistic.
Jewish Readers: DIY or Borrow Your Judaica
Seriously, do you want to spend $70 on a glass your going to smash? Use a lightbulb instead. With the exception of Kippot, Judaica is very expensive and wedding things are expensive so by the transitive property of cha-ching Wedding Judaica is astronomically expensive. Eric and I made our own Chuppah (and if you want a canopy for your wedding, regardless of religion, I suggest you make it yourself-- renting one was going to cost us ~$80) Plus when you make things yourself then you have a cool family heirloom and who doesn't love cool family heirlooms. Also check in to what your synagogue offers with wedding services (ours offered a Ketubah) and what your family has especially since you'd hate to drop $100 on a Chuppah cover and then have your grandma want you to use hers. If you're having your wedding at a synagogue I would skip buying kippot because you will end up with roughly as many kippot as you bought.