Try:
I have been hearing good things about you.
And:
I have been watching you from afar. I admire you for what you have done with your career.

Student or Learner
Hi Mohamed,
I am always hearing about you good. People are considering you as a role model of a best marketer. This what my passion about working with you so that I can learn.
I am following your successes from a step to another, for a while. I hope that I can reach 50% of what you have already reached in your career path.
I am worried that you might get annoyed of me keeping sending you. I am sorry for that but this is due my ambitions
Try:
I have been hearing good things about you.
And:
I have been watching you from afar. I admire you for what you have done with your career.
Not a professional teacher
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.