Let's start off with the basics:
1. The idea of tone, as most understand it, is simply about having relatively low body fat and being *somewhat* muscular. Muscular != "bulky", but make no mistake, the popular conception of "toned" involves a minimum level of muscle on the body.
2. For most men, you need to be 10-12% body fat to be considered "toned." But it's entirely possible to have very little muscle at these BF levels and completely miss the mark. This applies to both men and women.
3. Most people should not look to cardio to burn fat. It's generally an inefficient approach. Instead, look toward setting up the right nutrition plan. Cliff notes here: lower overall calories, keep protein high.
4. Train all muscle groups.