Gosh, yes, google can be very scary. I think Sheffield runs by the same laws as most big cities. Don't go out alone at night, don't leave your drink, wear trainers to go places then put on your heels once you're there ( in case you need to run ). Buy a r*pe alarm, and learn what's legal and illegal in the UK. Pepper spray is illegal, and you'll get in trouble if you're found to have it. There are legal self defense sprays you can buy. Take public transport over walking, the british transport police are helpful once you contact them, but the folks who work at stations usually ( no hate, just my experience ) aren't, so just go straight to the helpline.