I suggest you read this article in it's entirety including and especially the last paragraph
What I have found more successful than a free lesson is this; I schedule an extra half hour at no extra charge as part of the first lesson with the month in advance way I charge. It gives me a chance to do several things that will benefit the student without taking time out of the lesson. I get to look at the students instrument that they are going to use for the lessons to make sure it is playing all right. If the instrument is a problem, it gives me a chance to possibly adjust what is wrong, if it is going to easy to do. If there is a more complex problem it gives me time to go over what is wrong so the student or family can understand what the problem is. At this point I can explain what the options are in dealing with this problem. If the problem does not effect the first lesson we will use the instrument and work on getting the problem solved for the following lesson If the instrument can't be used for the first lesson I have options that will allow us to have the lesson anyway. I will use some of the extra time to set up a diary book that will keep track of the projects we are working on. In addition it gives me and the students or parents time to discuss other things of importance to get off to a good start and have a friendly relaxed atmosphere.
Additional reasons why my approach of an additional free half hour works efficiently. Free trial lessons that are offered by some studios are generally for only a half hour. This is not enough time do all the things that I want to do to get lessons off to a successful start. In addition, if after a free trial lesson, the student is not sure if they want to continue, other problems occur. If the student is not sure if they want to continue, then they usually do not buy the course material. The student goes home with nothing to practice and looses everything they might have learned. If the student then decides to continue, all the material from the free lesson has to be taught again and you really got nothing for free
Also, in my case I would not get the time to start our diary book which is partially why I allow the extra time. If the student decided to continue lesson this would have to be done during the first real lesson and I would have to review the things that we did again during the trial lesson. This approach is very disruptive and is a disorganized way to work. This basically means that the time for the first lesson had been wasted and very little was gained by it. My approach is let me do all I can so students can get off to a running start. In my case I put so much effort in trying to get a good start I don't want it to go to waste. I want to do an intense job on my end to help the student. I get the impression that I seem to care more about some of the students or families than they care about themselves.
Another problem with half hour lessons. I am going to break down a half hour lesson like this. If three minutes are used to get started and to pack up at the end of the lesson that leaves twenty four minutes for actual lesson time. This means a teacher can look at one original project for twenty minutes or two projects at twelve minutes apiece. Other possibilities for the teacher is to look at one of the original projects and add one new one for 12 minutes each, or use the 24 minutes for something new and don't look at an original item. I teach in a way that students understand and retain what they learn, verses playing by rote and superficial learning. Students with prior lessons are shocked at what they thought they knew but really did not as they study with me. I tell them they learned by rote and not with understanding with their prior teacher/s.
Reasons that I've learned as to why first lessons fail.
The teacher is obnoxious or shows a lack of interest.
The teacher is not skilled as a teacher, lacks patience and compassion, or does not have an organized lesson plan.
The student or parent is obnoxious or is not cooperative.
The student or parents try to ignore my studio policy that was discussed in setting up and arranging the lessons.
The student is too young and is not ready for organized lessons. To avoid this from happening I go over a check list with parents that I have developed. If parents are honest about the answers they give, this problem should not happen.
I do not have the teacher problems that are listed in the above list. I show serious interest in helping students in a very caring way. I am not going to be modest about my expertise in the music teaching profession. I've found that in every case that I have had so far in all the years I have been teaching, that the sooner people let me work with them, the sooner their results will improve. If I ever see or feel otherwise I will tell them they are better off with the teacher they are with and why. If you would not be honest it will be evident to the students/parents in the near future and you will look foolish. I have more pride in myself than to fall in that trap.
The natural progression of why a student does not work out in music in the early going
What I mean by this is a failure other than what was mentioned on the list of what makes first lessons fail. Typically what happens is this. A student starts lessons and after a few weeks it is evident that the student is not doing much practice. I start to explain the problem and suggest what and how things should change to the student and or parents of students that are below age 12. I go over the practice environment at home and see if it is conducive to learning. If I think changes are needed I will suggest them. This has helped many of my past students improve after having this discussion and changing things we have talked about. In addition I try some motivating or motivational conversations. I explain how other students have had this problem and how we worked together to change things and how they did much better afterwards.
I try each week to get better results through reinforcing what I have suggested. If I do not get any positive reaction to my efforts by weeks 7 through 14 I find that students will generally realize that playing a musical instrument is not for them. At this point I would have evaluated whether a different instrument would have been a better choice for them along with many other factors. I would have investigated and had discussions with students above 10 about what kind of music they listen to and why they decided to play an instrument and other reasons. If students are younger I would have asked the parent/s how the student ending up with the instrument they came to learn. A change of instruments has solved some of the lack of student interest so it pays to look into this situation. There were times when a parent forced the student to play a different instrument than the one they wanted to learn. This happens for different reasons. The instrument was in the house already or because a parent liked a different instrument over the one their child wanted to play and other reasons. Another reason I have occasionally suggested to parents to change the instrument was because I knew another instrument would be better for students ages 4 through 6 or 7. I would explain they will find the instrument I have suggested easier and more enjoyable to play at their age. I mention that they could add the other instrument later or go back to the original one at a later time rather than quit music altogether. I teach in a way that makes the second instrument so much easier to learn than the first instrument. There is a lot less to learn because the music end of learning has already been done properly and thoroughly if the student studied we me. We would just have to put the information that the student already knows on the new instrument. I own and play 18 different instruments so I know about these things first hand. I have the ability to teach over 20 instruments. The other instruments I don't own are played the same as ones I have and play. The only differences would be is that they sound different like more mellow etc.
The reason why I mention this very important information is to prove that a trial lesson does not achieve the results of my approach, unless it falls under the "what makes first lessons fail" that I wrote about earlier. When you factor in that I charge in advance only one month and not on a semester basis it lets students drop out of the lesson program after each month. As I have explained the student does not abruptly loose interest. This happens over a 7 to 14 week period for students who really started music lessons for the wrong reason/s. The way I charge is advantageously to this situation. The students who stop at much later time in their lessons are for different reasons than what I covered at this time.