In my experience as a tradesman, the most effective strategy to identify active buyers is by asking our clients to be on the look out for any others who face similar problems, to help their friends identify your comapany. After a job is wrapped up and when installation is proper and smooth; actively seek to encourage clients to help you market. A social media post of the work with the company can really help identify active buyers, especially if the work went smoothly from sale to labour and clean up.
This is similar to word of mouth in identifying active buyers.