What is the first thing you must know before attempting to disassemble or inspect a firearm?

The first things I need to know about a firearm before attempting to disassemble it is who makes it, is it loaded and how does the safety work. Knowing the make and model points me in the right direction and takes some guess work out. Knowing if it is loaded or not is important for safety and knowing if the firearms have a safety and how it works goes with that. After that it would be important to figure out how the make and model is broken down, even if just for a quick field strip for cleaning. Most Handguns have a takedown lever located above the trigger and trigger guard but this will change from brand to brand and model to model. A fair number of rifles use machine screws that need to be removed before disassembly and most shotguns require the use on a punch to remove pins for a breakdown. No matter the firearm, step one is safety and step two is learning the method in witch to begin your disassembly.