What advice would you give to an executive who is about to negotiate an employment contract? How would your advice be different if you were advising a non-unionized ,mechanic friend who is about to a

What advice would you give to an executive who is about to negotiate an employment contract?  How would your advice be different if you were advising a non-unionized ,mechanic friend who is about to accept employment at a company with unionized employees? Please internet reference only no more than 180 words. Thank you