You could include some of the following in your letter:
 the advantages of music lessons
 the disadvantages of music lessons – for example, the cost of instruments
 whether the school should invest in music education
Thesis statement
: Topic + M1 + M2 + M3
Topic : Learning music in school
M1
: Disadvantages: Time wasting, takes up effort
M2
:Advantages: Opens up learning paths, Gives a sense of relaxation
M3: Schools should invest in music education: Purchasing instruments, hiring teachers
Thesis statement: Despite the disadvantages that music education carries, including its time
wasting manner and energy consuming effort, the benefits outweigh the negatives; as music
education clears paths for students, and gives them a sense of relaxation. Thus, schools
should invest in music education, by purchasing good instruments and hiring qualified music
teachers.