Not all measuring cups are created equal. There are actually separate measuring cups that should be used for wet and dry ingredients. The Just A Pinch Test Kitchen shows how to properly measure ingredients.
To measure liquids, use a glass measuring cup.
Always read liquid measurements at eye level on a flat surface.
For sticky ingredients, coat the inside of the measuring cup with non-stick cooking spray.
Pack brown sugar into a measuring cup to get an accurate measurement.
Use a knife to scrape extra flour off measuring cup.