Peel and slice or dice. Or leave peel on, halve and remove large pit for scooping out and mashing avocado. Sprinkle cut avocado quickly with lemon juice to keep it from discoloring. Add to cooked and cold dishes just prior to serving. Store cut avocado with pit in, tightly covered in the refrigerator. If avocado is too green when cut, put halves together with seed inside, place in paper bag and leave at room temperature for a day or two to finish ripening. Or dice flesh and marinate for an hour or so in oil and vinegar salad dressing; this softens and ripens the flesh.