There are 7 basic watercolor techniques: washes, glazing, wet on wet, dry brush, lifting off, dropping in color and resist.

Washes: The most basic watercolor technique is the flat wash. First wet the paper, then apply the color on a sloping surface in slightly overlapping horizontal bands from the top down. Once complete the wash should be left to dry and even itself out - don't be tempted to work back into a drying wash, the results are usually disastrous!

A variation on the basic wash is the graded wash. This technique requires the pigment to be diluted slightly with more water for each horizontal stroke. The result is a wash that fades out gradually and evenly

Glazing is a similar watercolor technique to a wash, but uses a thin, transparent pigment
applied over dry existing washes. Its purpose is to adjust the color and tone of the underlying wash. Be sure each layer is thoroughly dry before applying the next.

Wet in wet is simply the process of applying pigment to wet paper. The results vary from soft undefined shapes to slightly blurred marks, depending on how wet the paper is. The wet in wet technique can be applied over existing washes provided they are thoroughly dry. Simply wet the paper with a large brush and paint into the dampness. The soft marks made by painting wet in wet are great for subtle background regions of your painting.

Dry brush is the almost the opposite watercolor technique to wet in wet. Here a brush loaded with pigment (and not too much water) is dragged over completely dry paper. The marks produced by this technique are very crisp and hard edged. They will tend to come forward in your painting and so are best applied around the centre of interest. Dry brush gives crisp, sharp details

Lifting Off: Most watercolor pigment can be dissolved and lifted off after it has dried. The process for lifting off is simple - wet the area to be removed with a brush and clean water then blot the pigment away with a tissue.   

Dropping in Color: This technique is simply the process of introducing a color to a wet region of the painting and allowing it to blend bleed and feather without interruption. The result is sometimes unpredictable but yields interesting and vibrant color gradations that can’t be achieved by mixing the pigment on the palette.