Getting Clients To Pay  

I would type up a notice and let them know you have to charge late charges for each day that the bill is overdue. So if they pay on time , they save money....and have them sign this before you do any work for them....! I would try to find clients that will pay on time so you dont have to work with those who give you trouble.

I just simply wouldn't give them the product unless they paid, then edit the content and sell it as a template and probally make more! I don't see why they don't pay, if they really didn't want to wouldn't they make there own? There just lazy incompetent arses and one day if they end up doing project based work I would hope that they have a crap time, just like you sound like your having.

That's why most companies that offer web hosting will want a credit card number that way they can automatically bill it every month. Pay Pal can also be set up to provide monthly payments. The customer has to approve it in his/her account settings in their pay pal but once they set it as approved for your monthly billing it will automatically come out. The only problem with that is if they don't have the money in paypal it may cause them problems but you still won't get your money.
If you can get up front payments it would be best. If you do good work then maybe you could have a portfolio or showcase of some kind with samples of your work. Then explain that your service works on a pre-paid 6 month lease or whatever terms you want to set. If they object just inform them of other peoples practices and that you hate to have to use a pr-pay service but the bad apples are forcing you to have to. In my experience if you give someone an inch they will take a mile. You need to protect yourself so you don't lose your income but you can still do it tactfully with the customer and they should understand if they are sincere. If not then maybe they are one of the ones that are more trouble than they are worth.

I haven't started freelance graphic and web design services. I'm on still of the process of learning web design and the freelance business. Your post is common to every freelancer around. I always see some blog post about similar incidents happened to designers.