How do questioners decide what advice to take and apply?

Assuming you have asked for advice on how to deal with a fairly serious problem that affects your quality of life or an important relationship and you get a wide variety of answers. Some advice may conflict with other advice.

How do you determine which person is qualified to give the advice they offer?

How do you decide which advice is sound and worth applying to your life and situation?

How safe do you feel following advice from anonymous strangers on the internet?