Principles &
Elements of (Interior) Design

There are five (some say 7) elements of design: 
* LINE 
*  TEXTURE
*   SHAPE or FORM
*    S P A C E
*     COLOR
For more detail see what Wikipedia says about Design Principles & Elements        CLICK HERE.
Principles (like verbs) & Elements (like nouns) of Design
Examples Below from Art

Basics of Lighting

Go to this commercial small website for current information on emerging led lighting calculations from a lighting retailer.
You want to learn how to put light into a room, why color temperature is important, basic rules to follow, and about the different types of lights that are available. New technology is also having a big impact in saving energy as well as making totally different lighting options available. You want to look at how lighting need is calculated and look at trends on the right of the page. This is a small company with a limited site but it has great basic information to start learning about lighting.
For a comprehensive look at lighting homes go to the Lightrays website.        CLICK HERE.
You will be looking at a 36 page pdf. Click the advance button and work your way through the document.