As far as business advice goes, AVOID
the sole proprietorship, get an LLC with some legal protection for yourself so you can't be raked for everything you own.
Besides that, it'll allow you to establish a consistent name and you can write off other things such as gas/mileage driven to gigs, etc.
I myself am not a freelancer...yet...but I've heard on many photography forums that the best place to start is your local community. I have a friend that contracts himself out to local families to shoot their kids' high school varsity sporting events. He charges a flat fee to get out there ($50 or $25 or $100 or whatever depending on number of kids/event) and then sets up the proofs on a website. Families pick photos they like and he charges $1 for each photo too.
If you have a local imaging/printing studio in your area, you can partner with them too if you get to know them. I know that might sound like competition at first, but if you do something that they don't do then a mutually beneficial relationship could happen.
get creative. Exchange your services for products or items or other service if you can get a favorable agreement.