Wah How to use If I were you,...

We can use this expression If I were you, ... to give suggestions. In fact this is the first part of a second conditional form. 
(See more in Wah How to use second conditional..)

    If I were you, I would consult a specialist. ( = I think you should consult a specialist.)
Or you could say 
    I would consult a specialist if I were you.
because they are normally reversible.

Note: We usually use were in formal English, even when the subject is I,he,she,it. 
           But in informal English was is acceptable with these subjects. 

    A: I forgot my umbrella in the hospital. 
    B: If I were you, I would phone the hospital right now. 

    A: I always forget things easily.
    B: If I were you, I would take a note.

    A: I feel terribly drowsy in the office.
    B: I would get some coffee if I were you.

In spoken English, we can use If I were in your shoes, ... instead of If I were you, ... especially when the person receiving the advice is in a uncomfortable or difficult situation.

    A: I saw my boss, who is married, kissing his secretary, who is not.
    B: If I were in your shoes, I'd keep my mouth shut.

    A: I found a wallet at the park with a lot of money in it.
    B: If I were in your shoes, I would call the police.

    A: I have had a terrible headache for a week.
    B: If I were in you shoes, I would see a doctor.

If I were you, I would take a break.

Wah How to use "What about...?"

1. We can use What about to suggest someone to do something.   
    I don't want to go to the library, what about going to the movies? (Let's go to the movies.)
    Rather than waiting here, what about going around? (It's better to go around.)
    I don't feel like working now, what about going shopping instead?
    I am on diet, what about having fruit salad for dinner?

You also use How about. They have the same meaning in making suggestion.
    How about coming with us? (Shall you come with us?)
    Rather than going to the cinema, how about the theater? 
    The traffic is very bad, how about getting there for a walk?
    Your brother is mad at you, how about apologizing your brother?