Both. No matter if you are a leader or follower, solo practice is essential to become better in couple dancing. The material in every lesson is presented and explained in the way so that both roles find it clear and easy to follow. I also use a few tricks, like counting in 4s instead of 8s and leaders can always skip the first 4 counts to join in later. In some courses I show demos for both roles: leaders - starting on the left - and followers - starting on the right. You can follow either one or both, I recommend the latter for more practice. At the end of the day our footwork is not that different. And the more you practice the faster you improve.