Cut to the chase - To get to the point, or the most interesting or important part of something without delay
Accident waiting to happen - A situation where there's going to be an accident or something will go wrong
Burn the midnight oil - To stay up very late working or studying
Notch on your belt - A success or achievement that might help you in the future.
Down and out - Desperately poor and in need of help.
Couch potato - An extremely lazy person who spends most of their time in front of the TV eating junk food
Clean sweep - To win absolutely everything in a competition or contest
Between a rock and a hard place - A position where you have to choose between unpleasant alternatives
Off color - If someone looks off colour/color, they look ill.
Bite off more than you can chew - to take on more responsibilities than you can manage.