As a guy who has had to change lawn care businesses a couple times here is why I have had to change.

1. Professionalism - Your average craigslist lawn guy is an ex con or just incapable of working for someone else. They don't show up when they schedule, they don't provide a full service. They don't call back. They look scary, which is a no go in a nice neighborhood. Ask what the client wants. Do they just want you to mow, or do they want you to take care of their lawn. Be able to provide what the client wants.
2. Price to service ratio - I have less sq ft of grass than I do house. It takes a crew of 2 about 20 minutes to do everything properly. I'm currently overpaying because it seems all reasonably priced people forget to blow or weedeat and it's annoying. Don't make client's call you back.
3. NOBODY wants to do flower beds or trim trees/bushes. Why? I'm willing to pay. The one I have now will do beds, but they way over charge, because they don't want to do it.
4. Offer people weekly bi-weekly and 10 day plans (eg - mowing on the 1st. 11th. 21st.). People have different budgets / needs.