While I lucked out and don't have to pay for my entire wedding on my own, my parents (who are divorced) are not made of money and therefore cannot contribute every dime either.
That being said, here is what I have been doing:
Reception Hall - you want to find a place to have your wedding that will include EVERYTHING (each and every course, dessert, champagne, booze, etc.) so that you are not stuck paying any extra fees. Reception halls are usually paid in installments. First a deposit down, then 2-3 more payments over the course of the rest of your engagement. This is nice because it gives you time to save up for each payment. Also, our place has silk floral centerpieces which I think are beautiful, so that completely cuts out any money i'd have to spend making my own. Check and see if there are any "house centerpieces" that you could use for your decorations.
Wedding gown - these are usually paid in installments too. Check out bridal stores that have "off the rack" dresses...which are gowns already made and set at a MUCH cheaper price than one that you have to order from scratch. All you have to pay besides the basic fee is any alterations you might want. Many places have beautiful "off the rack" gowns. Also, check out any bridal stores that have what they call "Sample sales" because those gowns usually go for very little. You can find beautiful gowns that way too...just be sure to check for any rips or stains before you purchase, as these types of sales are usually final and cannot be refunded in any way, shape or form.
Flowers - again, I am going to suggest the silk floral arrangments. Most of my friends that got married spent a good $6-$7,000 on flowers alone. That to me is ridiculous. Check online for silk floral arrangements for your bouquets. In pictures, you will never be able to tell the difference. And, they don't die on you at the end of the night ;)
As far as other money saving tips, the best thing I can suggest in your daily lives are these: bring your lunch to work, don't eat dinner out as often, cut out buying cocktails out at bars, make your own coffee at home as opposed to going to Starbucks every day, and keep shoes/clothes as long as you can without having to always keep buying new things. Believe me, these are simple, but HUGE money saver tips!! Believe me...I've been engaged for a year now and we've saved about $4,000 by cutting these out for a simple 12 months. Now we can pay for our photographer!
As far as coming up with the money to pay for things...depending on your finances, you and your fiancee can open up a credit card together that has a plan with the first 15 months interest free. If you are disciplined enough, you can charge what you need to for the wedding, and then write out a budget to pay it off on time before the 15 months are up. To make this work, you really need to sit down and come up with a budget on how you are going to pay it off though. This credit card plan simply buys you extra time to pay off expenses, so if you choose this route, do it cautiously so that you don't get hit with any back interest.
Feel free to e-mail me if you have any other detailed questions. Would love to help! Overall though, don't spend anymore money than you can absolutely afford to! While you want to have a nice wedding, don't feel that you have to spend 50k on a mere 24 hours of your lifetime. There are ways to do it for MUCH LESS! Good luck!