there is a few ways. if I were u, look around with a dowsing machine, or in lentimas town, there is a plane and behind it is a stair set walk up and somewhere is a fire stone. or if you wanna sharpen your battle skills, battle driftveil tournement a few and you wanna use your legendarys, choose every type of battle from the green dude or if you want a challenge, choose unova leaders from red guy and doing so allows you 2 practice, use legendaries, and get battle points for a fire stone from the guy on the right who sells junk 4 battle points. also you can do rental masters. I think the maximum amount of battle points you can get from a tournement is 16 from champions.