Designing your space is an art not to be taken lightly. People go to school for years in order to be properly equipped to handle coordination of furniture, fabrics, style, color, and architecture. Education is really an introduction into the realm of Interior Design. There also needs to be years of successful design experience before you are considered to be a professional. California offers a state exam for the added assurance for customers that they are getting an experienced and licensed designer.
An AA in Interior Design is merely an introduction to the tools and knowledge that interior designers have learned throughout history. There are some standards in the industry though. Designers in many industries go to school and learn The Elements and Principles of Design. The Elements are: line, shape, space, value, color and texture. The Principles are: unity, harmony, balance, rhythm, contrast, dominance, and gradation. Students are often supplied with Interior Design Standards such as common furniture dimensions; here are two lists of examples (http://www.cawspi.org/Furniture%20Design.pdf) and (http://www.crni.ie/wp-content/uploads/2009/11/Furniture_Dimensions.pdf). A few books that specify how much clearance the human body should have between furniture and space planning recommendations are books like Human Dimension in Interior Space by Julius Panero and Martin Zelnik and Interior Graphic and Design Standards by Reznikoff supply reference information utilized often by entry level designers. The books that I have are rather old. I am sure there are updated versions by now.
Other great reference materials that you can find online on sights such as Amazon.com. Two products that are listed is Home Quick Planner: Reusable, Peel & Stick Furniture & Architectural Symbols-Paperback by Daniel K. Reif (Author). This product sounds great because learning 3D design programs is time consuming. Sometimes it is easier to have products that make designing much simpler. The great thing about this product is the ease of use compared with paper, pencil, and computer programs.
In addition, Amazon also recommends books that other people have purchased listed on the bottom of the Amazon page. You will find books on color theory, the color wheel, and space planning all at discounted and even used prices. Come to think about it, I just may purchase several of these for my library. Hope this information has been helpful.