First: Only bring that which you can afford to spend in CASH. Cash negotiates and pays a flat rate, plastic pays the asking price + tax. Always remember on Sunday the less crap they have to haul back to the shop the happier they are, again cash is king. That said there are different rules for high dollar purchases (I’m talking well over $2K items)
Second: Cruz the show the first time at a quick pace. Note the locations and prices of things you are interested in and keep moving even if you are in search of unobtanium. Then compare notes and hit the places that have what you need at the better price or have more of the things you need in the same place.
If you need documentation in your location ensure you have it. Know the ins and outs of the 4473 and state paperwork. I live in an incorporated city, there are very specific rules for not filling out the “county” part of the form, know them if this applies.
Be prepared to shake your head, stifle a laugh or even bite your tongue. Do not “offer” your opinion on a conversation a seller and a potential customer are having. Its not your game, shut your yammer.
ALWAYS ask permission to touch, fondle or handle.
NEVER dry fire without explicit permission.
Watch where you point the bloody thing, if you can’t do what you need to do to ascertain functionality while pointing down at the table then you don’t need to be doing what you are doing.
Be polite, Be Professional and have a plan to make a new friend at every table you stop at.