Could a freelance dev let me know how they find clients? Not just the ones from sites online and such, but the good clients, 3-4 month projects, proper prices?

I usually find I get most or my work via my website and LinkedIn. LinkedIn for local people looking for a particular skill and the website is generally everything.

The key to being successful in freelance is word of mouth and marketing. You need to market yourself in the right area. Be specific about your skills. Just because you *can* use photoshop doesn't mean you should list it. Don't list too many skills, it can look desperate and spammy. Focus on the ones that matter most.

Become friends with project managers or freelance SEO / PPC guys. If you don't do design become friends with designers and if you don't code then become friends with devs. This cross pollination can work very well.

big clients start with small projects. it just takes time and a lot of small shit projects to find the long-term clients you'll love and who will love you back.

mouth to mouth. Do as max as you can to please your client, if he is happy with your job it will recommend you. Be gentle with them, don't charge for some simple tasks you normally will (30minute jobs for example) and he will love you.
Another great advice is to network as most as you can with people from web (and others). Actually im working on 3 big projects (despite others) and all of them was offered me by designers that i've meat.