I have sales expierence but not in web sites. Web sites are easy to sell though. I'm only just starting up my own business 😉 The advantage I use to have was having a product that simply put beat the rest 1000 times over. That helped but the price tag didn't.
The key to selling is creating a problem for the client but magically having the perfect solution right then and there. If you manage to create this senario you will sell everytime.
In order to achieve the above you have to learn as much as you can about the client and come up with problems for them. Say you have a client with a bookstore, they want to also have an online book store, easy enough just show them HOW easy it can be to add new titles to their site with a CMS. Create the problem of how to keep customers informed, snail mail sucks, postmen are constantly loosing mail to dogs etc. but with a customer e-mailing list there is no chance, apart from junk mail filters but we don't tell them about that do we 😉
There's a saying though, TELLING ISN'T SELLING, you could sit there and say you're services are great but what if you could get the client to say you're services are great wouldn't that be better? 😉 oh yeah.
Example. Our services offer a vast range of options for your business. Wow that was good, the client now thinks you're after his wallet, wife (or husband) and kids. To turn that into a question and getting the client to agree would be this... Mr client can you see how our services offer a vast amount of options for your business? now the client would say "yes, please take my wallet and empty it".
Bah. I hope that helps. If you want more examples, more details I can provide more serious info to yah.
Oh there's another key, value building... I could go into that but yeah... Its not for every service or business. If you are using php then you can pump value building.
No matter what the product, no matter what the service. You still have to sell it and yourself.
EDIT: In my signature is a link to a webmasters course on business stuff, it has a bit of info in there... worth taking a quick look at.