Lab etiquette is the term used to describe a collection of safe-work and consideration-of-others practices. Introducing students to this concept can be very difficult, since it relies on actually paying attention to other people and your immediate environment. Seriously, a student in a Genetics lab once told me "I didn't even see that" about a bright red sign on the door stating "Gloves OFF!".
Basically, lab etiquette comes down to not doing anything improper with your gloves. Latex or similar protective lab gloves are used with a set of background assumptions - chief among these, is that your gloves are worn to protect you, not your samples.
To save money (and, I assume, technical difficulties), most gloves are non-sterile. So wearing them while packing pipette tips, for example, is a waste - clean, non-sterile pipette tips are not going to benefit from being handled by clean, non-sterile gloves rather than clean, non-sterile hands. Yet people insist on informing me that I should be wearing gloves when packing tips - I will obey your instructions only when you can provide convincing supporting evidence. "Bits of skin will clog the tips" is not good enough - gloves are generally covered in powder, a by-product of the manufacturing process, typically of a much larger particle size than average skin sheddings. The box of tips is bound for the autoclave - any of my DNA or cellular material attached will be simultaneously heated to 121 degrees and blasted with high-pressure steam. Contamination is unlikely.
Gloves are also disposable - they have to be, because everything penetrates gloves, eventually. Latex and other materials used to make gloves includes pores - through which, that nasty shyte you're handling will eventually diffuse. So if you get something narsty on your glove, throw the glove away. It's really quite simple. On a similar vein, please stop re-using your gloves during the course of a day - it's nasty, and results in horrible crud on your skin.
The assumption I make when you are wearing gloves is that you are handling some substance that you, quite reasonably, don't want to conact your skin - and that your gloves are now coated with this substance. So please don't touch doorknobs, light switches, computer keyboards, or other "safe" objects with your gloves. This leads to the "no gloves in the hall" rule - which people flagrantly disregard all the damn time. I don't fucking care that you just put those gloves on, that you're not yet working with anything unpleasant, that you just stepped out for a second - TAKE YOUR FUCKING ASS-RAPING BUM-LICKING GLOVES OFF!!! Wearing gloves outside your lab is indicative of sloppy lab practice inside your lab - so I won't believe you if you throw any of the above asinine excuses at me.
I won't even get into the chronic, normal-human-behaviour stuff I see in gloved people - don't touch your face if your hand is blue, OK?