Advice for a newbie web designer.

Hi all !

So I planned on start my own at home web design business so that I can earn some cash. I'm a web design and Programming enthusiast, but how ever I'm a total newbie when it comes to doing business. So my question is, how should I host when doing a Web Design business ?

I have no Idea how to arrange the hosting. For example should I use a unlimited hosting package and host all the sites of my clients in that hosting account ? Or should I buy different hosting packages for each of my new clients ? And how do I bill the client? Do I bill him for the whole project or specific features I've added ? I'm totally confused and hope some of you experienced folks help me out

Thanks and Best Regards !
Hashen