You want to be eating fewer saturated fatty acids found in fatty beef and other meats, and also fewer trans fatty acids, found in all manner of packaged snack foods, including store-bought cookies, stuffing and rice mixes, and so on.
But unsaturated fatty acids, found in various cooking oils and other foods, are great for heart health—as long as you use them sparingly, since they’re high in calories. Canola oil is particularly low in saturated fat. Try it in dishes for which you’re not looking for a strong, oily flavor. Olive oil has a rich, full-bodied flavor. Dribble it onto salads and other dishes where you want the oil to assert its flavor. Sesame oil works great for Asian cooking.
In terms of spreads, opt for liquid or tub margarine rather than butter or hard margarine. They’ll be lowest in the kinds of fats you’re trying to limit.