You'd be surprised the worse they can do is far worse than say no. I have had dogs sicked on my, gun pulled on me, people chasing me down blocks away to bitch about litering their property.
That's a common misconception about starting at the bottom. Do not do what you don't wanna do, do not undersell your self. That's how you get taken advantage of, people will not pay you and you can't do anything about it, well legally.
I started with a front drive craftsman mower, homelight trimmer and blower. Loaded in the back of my old jeep Cherokee. I still have most of my customers from back then it is very much about the quality of the job, the inter personal relationships you build.
Treat your customers like family, don't forget to say hi and take the time to chit chat with them even if your in a rush. This makes them feel like you care and are apart of a family. It's harder for them to leave you when they feel that way.
Offer something nobody else does. Me personally I include free fertilizer to all my weekly customers in Exchange for proper watering. Nobody else does that, does it cost me? Ya about $150 a month but worth every penny.
Professionalism and appearance of you, your truck, and your equipment are just as important as the quality of the job. Do you look, act, and maintain your equipment like a professional?