For liquids, measuring cups will give you accurate quantities. For best results, check liquid measurements at eye level.
For solids, use cups only for estimating and for when an ingredient's exact measure isn't critical to the recipe. When you want accuracy in the quantity of solids, use a scale to weigh it. Using a scale is a must when making delicate sauces and pastries, where accuracy is vital.
Measuring cups sized to the top rim usually work better in obtaining exacting measures, since you can use a scraper, spatula or ruler to level solids.
Sliding cups make it easier to accurately measure and dispense pastes like solid shortening.
Remember, it's not safe to 'shock' glass measuring cups by taking them from one extreme temperature to another, such as from the freezer to a hot oven.
Multiple sets come in handy when measuring different ingredients, so you don't have to wash in between.
Tip: When preparing a tedious recipe, measure ingredients such as spices, flour, etc. into small bowls or containers ahead of time. This will save you time and aggravation while you're cooking.