Check my letter

[desp]

I am learning english and I decided to write about something. I've found the exercise(attachment)

Please help me to understand my faults.



Officer for tourism
Dear sir
I have seen you advertisment in one of the
British magazine, and I would like to apply this
job.
I am 18 years old and now finishing my school
course. I am currently looking for a summer job
before studying in university. I would be able to start
work in next month untill the end of august.
I have gained good experience during my study
here. I am living in London for 3 year and have
visited all museums and attractions here.
To be honest I always interested in history,
customs and traditions of England, especially in
London. Also from the childhood I was interesting in
English language and I think it will be easy to
communicate with any tourists. It would be brilliant
experience for me too.
I would be grateful if you consider my
application. I believe I would be a usefull member
of your team.
So, I look forward to hearing from you soon.
Your sincerly,
Dan



Could you fix my mistakes, especially in grammatic? What partition of grammar I should learn? Please, It will be immense benefit for me.

[Allen165]

Gil

NOT A TEACHER.

I think you may have missed a mistake.

"And I would like to apply FOR this job."

[desp]

Thank you very much!!!
I will analyze all mistakes necessarily.