Toning my arms

ok so my yr 11 ball is a few months away im of healthy weight but my arms are flabbyish like not toned so any ideas how I can tone them up , I eat a lot due to the time of the month kinda thing and boredom so anyways to prevent eating so much

wtf guys im 15 10 years ago so at 5 years old I was so aware of health issues I wasnt a fat slob I have always ate healthy but round the time of the month or in the hols I crave choc along with healthy food such as veg like I said im healthy weight I just need tone