It is often happen that, your friend did much better than you are, and you felt jealous bout it. There is nothing wrong though about being jealous, as long as you have full control over that feeling. Jealous can be very helpful sometimes, but without control, jealous can be dangerous. It leads you to envy(hasad). How is jealous ever be good for you? Here's how. When you saw your friend did well, be it in drawings, designing, running, acting, in academic whatsoever, you should use your jealousy as a catalyst for yourself to improve, to be up to your friend's level or better than he or she is. So, no worries about being jealous. It's natural, and it's harmless when you know exactly how to deal with it.
The next question is, how can jealousy be dangerous? First, when you see your best friend got number one in class, you were number two. You got beaten by him or her. You feel like you're no longer the best, you wanted to always be on top but he or she beat you. You are jealous of him, now getting all the congratulations and praises. Then you hated them, you don't want to be friend with them, you spread words around, like they cheated in exams. What become of you two then? Enemy?
Some says jealousy are hard to conquer, it really depends on you yourself, how to evaluate it. If you mean 'conquer' by suppressing the feeling itself(which to me is very impossible), then yes it is hard. But if you mean 'conquer' by controlling it wisely, then it is not hard at all. The important key is you value others more than yourself, but at the same time, you evaluate yourself on what need to be improve.
My friend is a better designer than I am, a better student, good at drawings, and colouring. Am I jealous? Yes I am jealous of what he's capable of. But it doesn't mean that I'm gonna struck a knife down his throat or spread lies or ignore him for the rest of my life. It actually help me to be a better person. I learn from him as at some part he learns from me. Do you know a jealous person is called by Shakespeare a 'green-eyed monster'? Do you want to be a green-eyed monster? Value your relationship with others, and that will help you get through jealousy. And in the end, you like being jealous, you like to compete in a healthy race with your friends, or others surrounding you. :D
p/s-I joke with my friend if I'm jealous. It's a good thing though, for as much as all the crappy things I said to him, I'm actually proud of him. :D