people are using search engines for everything including looking up local businesses so i think SEO would apply here
if you are a SEO consultant, you can examine the client's website's meta tags to see if the location they want to target (the location they are in) are deployed in the title, description and keywords effectively.
I've noticed a lot of local business websites put a lot of localised keywords in their footer. for example:
london plumber, london plumbing service, london heat & gas specialists etc.
I've seen many people do it so it must be producing some results right?
Finally there are many directory websites, lists, guides that are localised. You can try to get your client's website added to these websites, lists and local guides.
It might also be worth looking at what other local businesses have done, where are they listed and try to get onto the same lists/websites.