Исправьте ошибки, пожалуйста, завтра сдавать. Dear sir/madam Manager, I saw your advertisement and would like to get a gob as a waitresses at a hotel. It seems to me that I am a good condidature, because I have a lot of experience, I have worked as a waitresses last summer and had a excellent job. Also, I am cheerful, sociable and hardworking. I am available for interview on any weekday morning. I am looking for forward to hearing from you. Yours fouthfully, Helen

I am looking for forward to hearing from you — I am looking (!) forward to hear (какой инг, если инфинитив) from you - две грубые ошибки.
А так все вполне норм)
Ну и запятых много, они там не нужны. Обращение/прощание не в счет, есессна