oil loss please help

I have a 00 corolla and for some reason i am losing oil. The car only has 80K on it and i try to change the oil every 3K. I know its not burning it and can't find any place its leaking. Anything i can check or do??

Thanks

if you know that u are not burning it i would suspect an oil leak, on the corollas, ive found that the head gasket and front engine cover up near the near the tensioner are where ive found leaks to occur most frequently, id check these places first