Choose long and firm stalks that are not as dry.
1. Cut off the bottom near the root end, or base of the lemongrass stalk, maybe one cm. Also, cut the top grassy part, as you will only use the bottom 6" or so of the lemongrass.
2. Peel away and discard a few grassy outer layers until you reach the inner tender portion. If the lemongrass is too old and it's all dry, then you should beat the stalk with the back of your chef's knife to "tenderize" it.
3. Cut large enough sections to fit your needs.
4. If left in large sections, you can add to stir fries, broths, or rice to impart that lemon flavor but remove before serving.
5. If minced, or used in a food processor, you can add it to curries, soups and stews and leave it in and serve it.