The trick is letting people know you have a website - make sure you keep on top of Google ad-words or something similar so you are high on the list of search engine results - Oh and make sure its all over your van !!
Not sure how many jobs Ive actually got from mine, but when I'm quoting, I always point people to it for photo's, testimonials etc... and 9 times out of 10 that tends to seal the deal.
I also got a link to Facebook on mine where I can put photos on myself - it seems every bugger is on FB these days and its a good medium for work - got lots of jobs from FB where friends of friends see any updates