ColourYour main goal is aiming for a type of unity or harmony in your palette. This is almost always true. There are some that love to put horrible combinations of colors together for a palette, and this creates a really jarring effect. Try new color combinations. Use colors you normally would find horrible or ugly, practice! look around you and just study colors all the time! I find myself driving in my car and looking at everything possible to just know colour better. This is probably the hardest concept to learn about painting, it will just purely take studying and practice. It wont come fast and it wont come easy ( unlike shattered ) Dont just tl:dr.
Hue:The first quality in the study of color is HUE. It names the colors around the wheel. This allows us to distinguish one color from the other by name
Value:The lightness or darkness of a color. Of all of these three, value is the most important to keep in mind. If the value of a color is wrong, then the color is wrong!
Intensity:The purity or strength of a color. ( when working with trad. paint ) No color is more pure than when it comes freshly from the tube. When you start mixing or blending colors together, you change the intensity. High intensity colors are going to be located in the upper right and along the right side of your color selection in photoshop.
Tint: This is when white is added to a color ( or blended in digital terms, makes the color less saturated with more tint )
Shade:this is the opposite of tint, this is adding black to a color.
Color Temperature:Certain colors are generally associated with warmth and others with coldness. It is said that reds, oranges and yellows are warm while blue, green and violet are cold; being the greatest degree of warmth in red and of coldness in blue.
Complementary colors:The complementary colors are those combinations of two colors that are in opposite positions on the color wheel; they suggest a sharp contrast of color.
( note that the shadow of an object is the complimentary color opposite of the hue of that color. ) A complement will make a color look more intense.
Triad color schemeA color scheme in which 3 colors of equidistant distribution on the color wheel are used, e.g., red, blue, and yellow.
Analogous color schemeAnalogous colors are colors that are adjacent to each other on the color wheel. Some examples are green, yellow green, and yellow or red, red violet and violet. Analogous color schemes are often found in nature and are pleasing to the eye. The combination of these colors give a bright effect in the area, and are able to accommodate many changing moods. When using the analogous color scheme, one should make sure there is one hue as the main color.
Monochromatic color schemeA monochromatic color scheme consists of different values (tints and shades) of one single color. These color schemes are easy to get right and can be very effective, soothing and authoritative.[5] They do, however, lack the diversity of hues found in other color schemes and are less vibrant.
Applying color to your painting:Now this is a huge step in finishing your paintings. There are a couple options that you can do.
if you are a beginner, i recommend starting your paintings in black and white to get the values and contrast down just right. Even a lot of pro's do this from the start too. Once you have your values down, you can create a new layer and change the mode to overlay or color. You can practice and experiment and see if any of these fit your liking. But i don't recommend leaving your piece after you just do a fast layer. the coloring is the longest and hardest part. after you have layed down base colors, make a new layer set to normal and brush in the color. You then can adjust any lighting and other hue/value changes within the color on this new layer. You wont learn much if you start out by using overlay and color layers, but rather just brushing on your colors and experimenting that way. Good luck and lets see some tries! post some b/w images, then with color added!
Very helpful colour resources:
http://stuff.veekun.com/pkcolor/#p13
http://kuler.adobe.com/
http://www.colourlovers.com/But just remember, dont ever, EVER EVER eye drop colors and your palette from your reference image. if you do, shattered will find you and will snap your tablet + spine in half.