Some decorators don't charge design fee but charge fair market prices so you are getting their services free of charge through the purchase price. Decorators all work differently. You should establish an agreement in the beginning. Your first decisions should be color scheme and style. You should choose a color scheme that has a little life to it non- boring.
Some people look in magazines for color schemes.
Some people look at patterned fabrics to spark a color scheme. Some folks decorate around the colors that they look best in. If you have never had your colors done now might be the time to do so. By changing the values of the colors. In other words don' t have them all the same degree of darkness or lightness.