I don't generally solicit any business, and I haven't spent a nickle on advertising of any sort for the last 5 years. I still get more calls than I can manage.
If you wish to solicit a particular job, and have identified a specific problem, then find the managers by the method I showed you, and then MAIL a proposal to the owners of the property. Such solicitation will probably get pitched into the trash bin unless you effectively identify a liability problem that scares them into action.
Businesses that care about cosmetics will already have a tree service. If you are eye-balling that lovely property and a couple of trees that could use a little pruning... give it up. They already have folks that they call.
Focus on the properties that show dead trees not removed, large dead branches overhanging the parking lots, weed trees growing into the foundation or perhaps just the fenceline. Many of those potential customers either haven't noticed the work needs done, or figure they cannot afford the work, or just don't have the time to bother with getting quotes. Put it in writing, and let them mull it over. Send an updated quote 6 months later, when the job is looking worse and still not taken care of.
If you like the personal approach, walk in the door with your written proposal, and ask the minions who you should address your proposal to. Be sure to include a business card. Then drop it off and run.
Property owners do NOT like to deal with salesmen. They do like service providers that make life easier for them, however. Be that person and they will come to you year after year.