There are two trains of thought when it comes to approaching Art Gallery curators. One is to do the utterly professional thing with your presentation BY EMAIL, as per their website guidelines, wait patiently for a response and an appointment.
Then the other one is to just put your stuff in the car, have a decent brochure made of your best work - and it must be in a theme, not all over the place, everything but the kitchen sink. You must dress all nifty and preferably walk in with a mate like you want to buy the art on display. Stand around sniffing haughtily down your nose and wait for the Gallery owner to wander up to you, rubbing his or her hands in anticipation of a quick sale. This is when the 'ploy' kicks in (but you have to have the chops/actual stuff to back it up, else it falls down like a house of cards).
You nonchalantly engage in conversation, making sure to throw out odd things like 'we've just come from (insert huge corporate bank/hotel chain name), they are oh so interested in our stuff' (it's good to always refer to yourself in the plural - establishes that you are royalty)
This is when you kind of stand around, pouting, looking ever so famous and bored. Gallery owner will (on cue, regular as clock work so they say), cough, splutter, fidget before asking 'Do you have any examples of your work that I can look at?" ...
Now you've nailed it.
(aside: providing of course, that you actually DO have major corporate interest, brochure, artwork in your car).
I used the classic approach one uses when submitting a bit of freelance journalism to a newspaper when I contacted a North Norfolk based gallery recently. I did do a bit of research first (duh, I'm not completely moronic), as you do. That is to say, I checked out the kind of work this particular gallery handle, what the average prices of the works are, the artists they have on their books, their location, the name of the owners etc. etc. ... seemed like they might be a good fit for my .... er ... Art (with a capital letter, so that I treat it with respect). But nope, they very politely thanked me for sending my emailed enquiry/attached pdfs but said that they didn't think they'd be able to sell my work in their establishment. Which is a euphemism in the Art world for 'God, this stuff is SHITE!'.
But no, I have NOT been put off. One rejection slip is completely NOTHING. I had a lot of those in my writing career before landing a regular paying stint with the Saturday Star in Johannesburg - that lasted for over three years and only really stopped because I wanted it to. It takes time, patience, a lot of work, quiet determination, heaps and heaps of research to put together a really good pitch to a gallery. And you have to actually WANT your work to be displayed in that particular place - that, actually is the key. If you truly believe that your work fits that space better than anything else they have on their walls, then you will get represented!
This is why I'm not interested in art-online websites, e-bay or other mass-buying portals for selling art. Like with freelance writing, I am choosing the market I want my Art to be in FIRST and when I find it, we will have a lovely long life together.
Okay, get back to work.