Make sure you clearly indicate colors that you like or don't like. Many decorators and designers like to use both neutral and accent colors, and these may not be your favorites. By talking with the designer and clearly indicating what you like or don't like you will end up with a color palette that matches your need.
If you life by yourself, it is easy to choose a design or style that you like. If you live with partners, spouses or kids it may also be important to consider their personal tastes, likes and dislikes when choosing a theme or design format. A good decorator and designer will spend time talking with the family to ensure everyone will like the finished product.