What's your current weightlifting routine? If you're looking for tone, not bulk, make sure that you're doing more reps in less time with less weight. 5 sets of 10-12 reps with less than a 45 second break between sets at whichever exercise you're doing is usually good for what you're trying to achieve.
If you're really looking for a great workout routine,
check this out. It's a website dedicated to workout routines for marines, but has great guidelines for anyone trying to get in shape.