Do what diana said, go back to play the levels you haven't achieved expert on, and save as much money as you can, then buy all the upgrades at the same time and hire all the employees, once you have all the upgrades it'll get easier.
Another tip is after you've gotten all your upgrades, try dragging the 2 people ones first so you can free up some space at the waiting area so more people can come in, try to get the others to wait to pay at the cashier, then cash them out once the line is full. so you can get the people who are finishing up to the next section, and drag more waiting customers to change their clothes, and let more in, you'll be able to pass the level and even get expert, took me a few tries to get it lol. good luck and happy gaming!