For a small solo guy, a one man show - I would recommend either setting up a DBA or just using your own name - both mean you are a "sole proprietor" . A DBA doesn't mean anything, it is just a made-up-name, but will make you look more legit to people who think you need a "business name" to do business. This DBA will also enable you to get a business bank account in that DBA name, and then you can accept checks as the business DBA name. Note: there is a drawback to this. It is that banks charges all kinds of extra fees for business accounts that they do not charge for personal accounts.
Setting up an LLC is just going to complicate things even more, and is not adding any value for you as I believe it will not offer you any liability protection in your scenario.
So, my advice for you-a person who wants to build a small lawn care business...is get a DBA, put it on your business cards...it will make you look more legit than your own name.