An apprentice of mine told me last week that he'd picked a neighborhood nearby, wrote estimates out for the obvious work that he saw needed being done. Before he knew it, he's done $5,000 in estimates. He had two jobs from it already on Friday, and he'll get more jobs just as a result of being 'out there'.
When I began, like the first week as a super noob, I had a networking strategy. For my customer, I would do something for free. And I would list it on the estimate, in red, the brief description, and the word Free.
When doing the final walk-through, you let them know you did this nice thing for them, at no charge. If you do excellent work, you can almost always expect a compliment right at the end. That opens you up to plant a marketing seed. It might go like this:
"If you really appreciate my work, will you do me one favor...?" and make sure you've got their full attention. "Will you tell one person? That's the best compliment you can give me."
Referrals are your bread and butter. WORD OF MOUTH IS GOLD. It is free. All you have to do is ask.
I have had that above scene hundreds of times. You almost always do SOMETHING free for a customer anyway, so give something, put it in writing, and ask for something. It's magic in how simple, cost-free and effective it can be, in both the short term, and the long term. It sets the stage for win-wins, trust me. Good bidniz, having hundreds of folks out there actively using your services and telling their friends about you. Welcome to residential tree service, 101.