-do a great job (& hope your rep builds up your list of students)
-advertise every where you can (craigslist, carry business cards, post flyers etc).
Making money is the chief complaint for most guitar instructors and it can be quite challenging to make a living from it.
For doing it properly... while I haven't taught guitar, I have done a lot of teaching in other subjects, so here's some pointers I'd offer:
-make sure you know the material you are going to teach down pat. Have this material ready to go before the student arrives. If you need to give them a hand-out or scale chart, have it ready before the lesson, don't write out scales during the lesson, you're wasting their valuable time.
-have a neat, clean, private & orderly environment for the lesson. Make sure it is free from distractions such as your phone going off during the lesson.
-have gear ready to go... if you need a couple of practice amps, have them ready... along with spare patch chords in case one goes out during a lesson. If you're just teaching acoustic, then no problem, but still have things like spare strings, and a tuner handy.
-have a metronome (most tuners combine them) and use it.
-if you're going to teach electric guitar, take a look at something like the BOSS JS 10. It allows you to plug in two guitars, each with their own effects, and play along with jam tracks.
-you might want to consider creating a website where your students can view or download material prior to lessons. This way they can be ready with the lesson material when they show up.
-the most important asset the student has is YOU, right there in front of them... make sure they understand the material covered before they leave. It is much better to cover less material thoroughly than to over-whelm them so that they can't remember how to play what they worked on during the lesson when they get home.
If you do it really well & keep it professional, you'll enjoy teaching and your students will likely enjoy the lessons a lot more.
Good luck!
