If you fill the frame, you've solved the question of composition and balance. However, you might want to avoid my experiences with bears. A Difference Protect your film . Store it in a cool, dry location prior to use. Never place a film container in the sun for any length of time.
Heat can ruin the emulsion.
Professionals routinely refridgerate their film. Keep the camera lens clean . Dust particles and smudges can ruin an otherwise great photograph. It's very time consuming and expensive to retouch photographs. However, this makes it even more important to take more than you think you'll need.