Who is asking: Student
The trick is not to look for shortcuts, and not to believe in shortcuts. It's like saying that taking the car is a shortcut for jogging. But you do the jogging for the exercise, so if you take the car instead, you don't get the exercise. Think of it that way: math is like jogging; you will get better at it if you don't look for shortcuts.
Rebecca, I want to add something to Claud's reply. I don't know if it is a "shortcut" but the way to be reasonably good at ratio and proportion problems is to be good at working with fractions.