Methods of Applying Paint:

Underpainting - for a tonal composition in one color or one in grays; painting the canvas the darkest tone - not usually any lighter than raw sienna; underpaintings must be thoroughly dry before glazing with other colors.

Overpainting - any paint applied over a base coat, whether alla prima or a glaze, scumble or combination.

Glazing - thin, transparent film of color through which the underpainting shows; cannot mix with white (opaque); any strong color which keeps its intensity when diluted with lots of medium (with turpentine and oil) can be used; glaze small sections with a good sized soft brush; underpainting must be dry; don''''''''t glaze w/ cerulean, Naples yellow, Mars violet, or Indian red; darkens the undercoat.

Scumbling - used over a dry underpainting; can darken or lighten the undercoat; use opaque paint, meaning the mixture contains white; apply lighter, brighter, dry consistency (no medium) of paint by rubbing a small amount of paint over the surface, using an old, stubby brush with short, soft bristles; gives a dusty or hazy look; can be used to lighten tones in background.

Dragging - dry consistency of paint is used like in scumbling; use a good brush dipped into dry paint, lay it lightly on the dry underpainting and drag brush delicately across.
Alla-prima - Italian "at once" - the direct approach - applications of opaque mixtures of colors in shapes, consistency is thick to absolutely cover the area over which they are applied; sometimes called "wet-into-wet;" there is no underpainting or overpainting; all painting fundamentals are combined in one coat of paint.

Impasto - Italian - thick, dramatic brushwork, creating texture using buttery, pasty paint directly from the tube; saved until final steps of painting; be selective when adding impasto texture, use short, stiff-bristle bright and paint directly from the tube with no medium.

Color mixing on the canvas - magical quality of oils is slow drying time, after blocking in of colors, use a smaller filbert and stroke by stroke add color to the wet surface; leave gaps between strokes to let underlying color show through; colors blend physically and optically.

Expressive brushwork:
-Be selective about detail - have strokes follow the direction of the form; use as few strokes as necessary to make the subject look convincing.
-Put thick paint against thin.
-Use brushwork to create texture - use thick pasty paint (no medium).
-Use brushwork to create atmosphere - dilute paint with lots of medium.

Other Terms:

Chiaroscuro - technique of using light and shade in pictorial representation
Plein air - technique of painting on site
Toning the canvas - done before painting - with either acrylic thinned with water or oil paint thinned with turpentine.