Eating healthier advice!

I am 16 years old and I really want to start eating healthier, in order to improve my figure, I'm working out too. 
But is there anything that should be cut from my diet that would help me to be healthier. 
I thought of cutting gluten from my diet? Would this even help?
I'm eating yoghurt with fresh fruit or gronola for breakfast. 
A salad for lunch with a piece of fruit. 
And whatever my mum cooks for dinner - pretty much always healthier. 
But it doesn't seem to be helping me so I was wondering if there's anything I  should try??