To elaborate further on what @J Scott mentioned I would say invest time in optimizing your website. Here are a few tips:
=> Have a modern design with a clean structure, responsive for mobile
=> Put photos of your properties and bio of yourself
=> Check out how fast it opens
=> Have important information easily accessible to your potential customers
=> Integrate Google Analytics, check your daily traffic and analyze the information e.g. high bounce rate means your potential online lead are exiting fast due to lack of interest content usually
=> Focus on particular keywords, optimize for search engines
=> Offer great content, quality information that is useful for your leads and check your page rank
=> Build a brand utilizing Social Media e.g. Twitter and Facebook
=> If your budget allows it try with online real estate advertisements
Also, I ran into a new startup offering live audio and video chat for online leads, can see who is your browsing your listings at the moment, can connect with them instantly and put a human factor in play, establish a relationship. I believe the name of the company is icfloortime or something like this.