Uniform requirements vary slightly depending on the business, so it's important you check the Stint's details before you accept it.
There are 8 basic items that will enable you to do all Stints:
A white formal shirt
Make sure it is formal - with long sleeves, buttons and a collar. The sleeves should be all the way down to the wrist (not to the elbows / shoulder-level). A white t-shirt unfortunately doesn't count. It's important to look smart, so make sure you iron your shirt and try to keep it free of creases!
A black formal shirt
Similar to the white collared shirt, make sure it has long sleeves, buttons and a collar. Nicely ironed too!
A black t-shirt
This should be completely plain - no patterns or logos.
Black formal trousers
These should be formal full-length trousers (not jeans, leggings, or tracksuits), with no patterns or logos.
Black jeans
These should have no rips or patterns and should be full length.
Black formal shoes
These should be black, leather-looking formal shoes. No trainers, plimsoles, boots or Doc Martens.
Dark, clean trainers
These should be plain and dark (black, dark grey, brown etc) - without white ticks, or patterns.
And finally... plain black long socks!