Here`s a picture
along the lines of some of what you might have on your own site. You can`t just copy it, but perhaps you can create something similar. Or maybe you already have some photography in your marketing materials you could scan.
I did a search in Google Images for "lawn sprinkler systems" and found many results. This site
is only one of many.
It doesn`t matter that you have no walk-in business. :-) What matters is that you get your company name out there, and what it is you provide to people that`ll make their lives easier.