Useless advice

That's sometimes the best advice. If they're giving you advice it's a task you likely must do without them, so once you're there you'll stand or fall on your own. There's no sense worrying about failure since if you don't fail you worried for nothing, and if you do fail that's simply how it is, and you'll need to keep going. People who say this likely care and want to show support, and sometimes don't have anything useful to tell you. They may not know enough about what you face or may feel you know as much or more than them and don't want to be patronizing but still want to be there for you. If they notice you seem nervous other people likely will too, and most tasks are more likely to succeed or go easily if you have the appearance of confidence and ability. You can't just "become relaxed" but you can do whatever it is you do to calm yourself down.

It's supposed to be a confidence boost, you spaz.