Types of common stains and how to treat:

Blood: Peroxide, if stain remains, use rust remover
Chocolate: Work in Fels Naptha Soap and 20 Mule Team Borax. Let sit 30 minutes then launder as usual
Coffee: Peroxide. If stain remains, sponge w/ dry-cleaning solvent
Cooking or olive oil: Apply dry cleaning solvent. Work to center to avoid ring. Blot. Apply light detergent solution. Rinse. Blot.
Crayon marks on walls: Spray on WD-40. Wipe w/ dry paper towel. Apply liquid dish soap onto damp cloth and wipe again.
Food Stains: Club soda (the mineral salts in the soda do the work)
Grass stains on clothing: Blot with rubbing alcohol. Let sit 30 minutes. Launder as usual.
Gum in carpet or on clothing: Use aerosol gum freeze or ice cube to harden the gum and make it brittle, then break into pieces. Scrape them up with a dull butter knife. Remove residue with dry-cleaning solvent.
Ink: Sponge w/ detergent solution; rinse. If stain remains, saturate w/ cheap hair-spray and blot. If still there, try alcohol, non-oily finger nail polish remover, and a bleach safe for that fabric, in that order. If a yellow stain remains, try rust remover.
Jam/Jelly: Dampen with water. Treat w/ Borax. Let sit 30 minutes. Launder as usual.
Ketchup: Peroxide
Kool-Aid on carpet: Spray with carpet stain remover. (Don't have any? Use shaving cream!) Blot with damp cloth
Lipstick: New stain: Waterless hand cleaner (kind used by mechanics to remove automotive grease.) Old stain: Spray on WD-40 Let sit 15 minutes. Work in undiluted dish soap. Launder as usual. OR: apply dry cleaning solvent and blot repeatedly until gone.
Makeup on clothes: Try Huggies Baby Wipes. (Because of the glycerin)
Mildew: Sponge area with disinfectant solution:blot. Bleach with chlorine bleach if safe for fabric (careful!); if not, use hydrogen peroxide.
Mud: Allow to dry, and vacuum or brush off as much as possible. Apply detergent or ammonia solution. Blot. Rinse. Blot dry. If stain remains, apply dry cleaning solvent. Blot dry.
Mustard: Peroxide
Nail Polish: Blot acetone or non-oily nail polish remover through the stain into a clean absorbent pad. No acetone on acetate, modacrylic, silk, or wool, use amyl acetate, from a pharmacy. Flush with dry-cleaning fluid; air-dry.
Pet Stains: Blot out all liquid possible by placing a clean towel on the spot and standing on it. Apply bacteria/enzyme digester according to directions. When dry, remove any remaining stain with detergent solution; rinse.
Red Wine: White wine, white vinegar and definitely club soda always work.
Rust: Rub with steel wool or rust remover. If you use professional rust remover be careful not to get any on your skin. Don't apply it to glass, porcelain or enamel surfaces. Rinse, blot dry.
Soft Drinks: Blot up all you can. Blot with detergent solution; rinse; air dry. If stain remains, soak with glycerin for 30 minutes.
Tar: Scrape up all you can, then remove residue by blotting with paint thinner or dry cleaning solvent. Blot with detergent solution; rinse, blot dry.
Tomato Sauce: Corn starch
Vomit: Scrape up as much as possible. Apply bacteria/enzyme digester according to directions. When dry, remove any remaining stain with detergent solution; rinse.

More Stain Removal Tips

Mystery stain? Look. Feel. Smell. ASK!
Be careful with bleach! It strips color!
Most old stains are damage and won't come out.
Remember, there is no magic in stain removal. All situations, surfaces, and materials are different. Good sense, timing, and technique are the best defense.