Letter

Dear Mrs. Jones,
I am writing to apply for the position of a coordinator in Campers’ Club as advertised in the local sports magazine.
I believe that I have all the necessary skills for this post since I have worked as a part-time baby sitter. Because of this, I am convinced that I would get along with the youngsters. <- (a more commonly used word would be "kids" but "youngsters" still makes sense)
In addition, I am a very energetic person who has all the patience needed to work with children. Furthermore, I am a nature lover and have been number of times camping a number of times.
I think this job would be a great opportunity for me to go camping once again and spend some time with kids. Hope to hear from you soon.
Yours sincerely,

I only made a few minor changes to make it flow a bit better. It was written very clearly already. Good job!