Complimentary colours on a standard color wheel they are the colors opposite each other (red/green, yellow/blue). They look great together and compliment each other. They make people feel good when looking at them.
A serif is slight projection finishing off a stroke of a letter. Sans serif means without that stroke. When you chose text for your designs you choose between serif fonts and sans serif fonts. They both have their place and can have a big effect on how your message is read.
Contrast can be an affective design tool. It can create a lot of interest in your designs and also add dramatic effects. In this example their are two types of contrast: shape and texture.
A drop shadow is a visual effect consisting of drawing what looks like the shadow of an object, giving the impression that the object is raised above the objects behind it.
Light is the essence of photography. Look carefully at how light falls on objects at different times of day. If you take advantage of natural light you can produce beautiful photographs that can be incorporated into your beautiful graphic designs.
Grey/Gray can be a useful backdrop for a splash of colour/color. Its a great technique for creating dramatic effects and bringing a key element into focus.