So i'm 104lbs and want to either lose a few pounds, or get in better shape and gain some muscle..how?

So i'm 104lbs, i wanted to lose a few pounds but now i'm thinking toning up a little, and gaining some muscle might be a better idea. So i'm just wondering how i could do that? I've lost weight before, about 50lbs, but i did it by not eating and with 0 exercise, so i don't really know how i should do it. I recently started running about a mile every day (hope to increase it over time), I joined a weekly kickboxing cl, and i play tennis or something like that once or twice a week, will this help me gain muscle?