A very simple rule that's easy to neglect.
If you don't ask for things, you don't get things.
Don't confuse this with “be an arrogant idiot that feels entitled to something“. That should never be the case.
However, many times in life if you don't ask for something, you won't get it. This is more a rule than an exception.
Want someone to help you? Ask for it. That person might be perfectly capable and willing to but will assume help isn't needed until you ask for it.
Want something to happen? Ask for it.
Want your deadline extended for XYZ? Need some more time to do XYZ? Ask for it.
Want someone to buy something from you? Ask for it.
It's utterly simple, but most people ignore this.
Needless to say – always stay polite and respectful, and be grateful for what you receive.