Watch the gallery owner get the special glint that says they think they just made a sale. Wander back to consult with your companion, then, you should probably leave, because the gallery shrew will jock you endlessly for the balance of the evening. I know I say this about everything, but wear good shoes . This will give you the credibility to pull off all these slick dance moves. People do notice, because remember, the function of the opening is to find out who's got the money, and then take that money away from them.
Shoes are key.
The advantages to getting really good at these events is they can open a whole world of better events. A final cautionary note. The most important person in the room will appear to be some European guy with slick hair and an untraceable accent. This is a guy from Staten Island looking for a rich patroness or patron and is definitely a sleazeball. Unless you want a live-in boy toy with expensive tastes, avoid him like the plague.