No water at all
First the breaker. Find the one marked well or pump in the panel and look at it. If it's tripped, reset it once and give it a minute. If it holds, you're done. If it trips again, leave it alone, because something down there is pulling too much current and a breaker that keeps resetting will cook it.
If the breaker's fine, look at the gauge on the pressure tank. Zero means the pump isn't running. Tap the side of the pressure switch (gently, it's got wires in it). If the pump kicks on, the switch contacts are burnt and that's a cheap part. If nothing happens, it's the pump, the wire, or the control box, and that's us.
If the gauge shows pressure but no water comes out, the problem is between the tank and the faucet. Check for a frozen or broken line, or a valve somebody closed.
Try the breaker and the tap. Then call.