I agree with the above ,
different methods of learning for different people. some folks are visual learners, some learn better by ear etc.
Lesson can be very important early on and make a huge difference, but not all teachers or teaching methods are created equal. again differnet ones will suit differnet people, Id recomend finding a good teacher through the recomendation of someone else who has had lessons (even if on another instrument) if you can, if not give it a go with someone, and if you dont have chemistry with them or they make you feel frustrated, dont give up the instrument , find a new teacher.
Bare in mind, most instrument instructors are not trained and acredited to be teachers persay, they are usualy just someone who was experienced on an instrument who decided to teach it to others at some point. Like anything, some folks have a passion and talent for teaching, and do their best for the student, others are just out to make a few bucks. Asking a lot of questions before you sign on with someone can help determine if lessons and that teacher is right for you.
suggestions on a few questions to ask:
what kind of experience do you have on the particular instrument?
How long have you been teaching?
and how many students have you taught on average?
In what styles of music do you teach?
Are there any specific books and materials you work from?
what are my requirements as a student?
what specificaly will you be teaching? (especialy important if you want to learn things like notes and sight reading)
as well as what their policies are on payment, missed lesson etc.
hope this helps