Not sure about a solution in your case, but some advice I can think of for new teachers is make sure you have a clear cancellation policy upfront.
One thing you get a lot of when you've got a bunch of students is cancellations at the last minute. Which basically means you've got to sit around for an hour earning no money. Make sure they pay you for a full month ahead of time and get it in writing for them to notify you at least 24 hours in advance of cancellations.
Unfortunately, you may have a bit of a problem with your timing. Summer isn't the best time of year to start a guitar teaching business. Most students consider summer to be 'vacation' time.
You'll actually get most of your sign-ups for kids wanting to start lessons in September when they go back to school. Hence the reason why all the music stores start advertising lessons in August.