Even National Geographics prefers people with majors that are not photography and who have taken some photography courses. http://www.nationalgeographic.com/faq/careers.html#photographer

I started weddings after shooting for a couple of years (3 years with a DSLR) mainly for fun.

Wedding photography is more like 90% business with 10% shooting.

I jumped into the deep end and would have gone belly up like most people do if a wedding photographer hadn’t taken me under his wing and shown me the business side of things.

I started this year and looks like my income will be about 12000$ (before taxes and overhead). Due to illness at the start of the year (was put into a coma for 8 days then spent a month recovering), I missed out on quite a bit of opportunity but with my current contracts I’m on line for that target … I also spent 2400$ in promotional efforts and plan on another 2000$ before year ends. I’m currently doing this part time now so if I can meet my 12000$ goal, i’ll consider this year a success and my target for next year will increase to 30000$. I’m doing this part time right now so my main contract is helping me not starve and allowing me to ease into it.

The most important lesson I’ve found is "don’t undervalue your services". Think like a business person. You need to pay income tax, perhaps sales taxes, buy raw materials (prints, albums, cd’s), put money aside for extra gear, new gear, gear rental, promotional efforts, regular overhead like an accountant … and you need to pay yourself.

You’ll need 2 or 3 of pretty much everything (Cameras, lenses, flashes … tons of batteries and cards) … suddenly you are looking at 8000$ in gear and that’s not top of the line gear either but prosumer gear (T2i, T1i or Xsi with a LSeries lens or 2 and a couple of Speedlights).

Remember also that you aren’t just charging for the time you are there shooting but post processing, meeting with the client … and that your woek might not be regular so oyu need to afford yourself a bit of padding.

You’ll find that 100$ an hour for a shoot translates to like 10$ an hour when you factor in all that time.

It’s also important not to undervalue yourself so that you don;t kill the market and don;t get a reputation as being a "cheap" photographer.
References :

talent
cool head at all times
plenty of equipment – and redundant equipment (just in case)
imagination
check out other wedding photographers
start small/help out another photographer
References :