You're well on your way to becoming your own decorator. The next step is to measure and plan, something that educated interior designers are experts at. In fact, most interior design schools require that you draw a scaled design plan as part of the application process.
To find out how to measure and plan,
First, take measurements of all of your furniture, rugs, and larger accessories you're going to keep. Then, either using some graph paper and pencils or an online interior design software like Floorplanner, draw out a floor plan for your room. If you use paper, it helps to cut each furnishing out, so you can move them around. Play with various arrangements, thinking about things like lighting and glare, focal points (TV, fireplace), and seating arrangements. Keep your lifestyle in mind. If you have a lot of cocktail parties, you'll want to center your living room seating around a coffee table. If you're more of a popcorn and TV family, you'll want you seating to face your flat screen. Once you've arranged your existing furnishings, take note of what should be on your shopping list!