This is a mature industry and most businesses will have an existing supplier. It becomes about doing something different or more likely better; e.g. getting in quickly with new companies, as Porky suggested, or being there when a dissatisfied company looks to change supplier.
It amazes me how many companies don't return calls, or make it easy to get in touch and get a quote. So doing something better could be returning calls really quickly, or even better, having an online quote tool that gives a quick accurate quote and lets people book a call back to finalise everything at their convenience.
In terms of capturing a company looking to change supplier; that will be about online visibility (SEO or PPC search/local Google Business Profile ads) for the relevant searches, a good website, great reviews, services and testimonials that convince people to go with you.