What should a pilot do if they are unsure about an ATC instruction or clearance?

What must a pilot do before flying IFR (Instrument Flight Rules) on VATSIM?

Select all of the current, real-world weather parameters that pilots must utilize at all times during all phases of flight while connected to the VATSIM network.

In the United States, while under radar contact (e.g., actively being controlled by ATC), when you receive a handoff to another controller, you should check in with your present altitude and, if it applies, the altitude to which you are either climbing or descending.

For example, "New York Center, American Ten, Three Thousand descending to Two Thousand."

This question is in reference to FAA/US procedures as the definition of "Monitor" slightly differs in ICAO 4444.

When ATC instructs a pilot to "monitor" a frequency, what should the pilot do?

When is it appropriate for a pilot to disconnect from the VATSIM network?

What should a pilot do if they are unsure whether they are in a controller's airspace?

What should pilots do if they are unable to comply with an air traffic control instruction on the VATSIM network?

A new pilot on the VATSIM network wants to ensure they are prepared for their first flight. What strategic planning steps should they take to enhance their experience and compliance with network regulations?

What is the significance of the "Tail Number" in general aviation callsigns?