If I were you means if this were my situation, if I was the person in this situation - " I'd play it" - or I would " play it by ear." To play something by ear means to wait and see what happens.
” If I were you 意思是如果这是我的情况，如果我是这种情况下的人——“我会玩它” ——或者我会“见机行事” 。 见机行事意味着等待， 看看会发生什么.