workout tips?

Hey everyone, I am getting really into the gym lately and am focusing on getting really toned as I don't need to lose weight (well maybe a little but not much) does anyone have any tips on getting toned? I'm particularly interested in learning new ab workouts that don't hurt my back. I do planks for my abs but want some other Excersises to vamp things up. My boyfriend is away and I really want to wow him with my progress when he comes back! 😝😝😝