[kangeki]

For toning, I love the "8 minute" series of workouts (you can easily find it on youtube). I do 8 minute abs and 8 minute buns 6 days a week. It's pretty convenient and works really well. I also do a few 1 minute planks for abs, and sprinting 3 times a week. So far this routine has worked out pretty well for me. I'm the same as you, I've always been pretty slim. I was never happy with my body though and I always thought it was because of my weight (I thought I was too fat), but then I realized that I just wasn't toned.

I haven't done yoga, but I know it's designed for toning so that might be good too. Good luck!