Pin your hair back. Wash your face so there are no oils and dirt on the surface to interfere with makeup.
Cover blemishes with concealer. Use a small brush or the tip of a sponge to dab (not rub) it on. Smooth foundation out toward the hairline, then under your chin and over your neck and chest. Apply base to exposed ears, hands, arms or legs. Set foundation with loose powder.
Brush eyeshadow onto the fold of your eyelid. Pick a dark color for depth. Add a lighter shade above your lashes. Sweep highlighter under your eyebrows.
Outline your eyes to exaggerate them. Draw a line close to your lashes, at the inside corner of the top lid. Extend the eyeliner up and out from where your eye curves. Repeat for lower lashes but extend the line straight across. Fill in eyebrows with pencil. Apply mascara.
Smooth blush on the highest part of your cheeks. Add a darker blush, contouring powder or eye shadow to the recesses under your cheekbones and the hollows of your temples to add dimension. Shade the sides of your nose to elongate. Blend.
Line your lips in a natural shade. Fill in with a comparable shade of lip color, unless your character calls for bright lipstick. Set with powder and add another layer of color.
Add embellishments. For wrinkles, dip a thin brush into dark shadow. Furrow your brows, crinkle your eyes, turn your mouth down and fill in these natural wrinkles with the shadow. Apply a dot of red lip color to the inner corners of eyes to brighten.
Sketch costume ideas, or flag examples from books and articles. Pick defining colors. A comic character with a dark secret may wear bright, clashing colors with a splash of black. Discuss your ideas with the director and costume designer because they may have a "look" that they want to achieve.
Sit, stand and rehearse in your costume. Check for fit, look and feel. You may notice you stand taller, or that the material weighs heavy on you and, as a result, your character. Discuss needed alterations with the costume designer.
Carry a special trigger object, something personal and hidden that recalls memories and emotions corresponding to those of your character. For example, if your character is unhappy over a lost love, you might carry a ring that reminds you of a sad breakup.