You really want to avoid keeping them somewhere that gets too hot or cold. 5 degrees is the ideal temperature but never let them freeze or they develop a strange sweet taste.
Keep them dark as well, light encourages greening and green potatoes are actually harmful for you to eat. My other tip is to drop a few slug pellets in the sack when storing potatoes in case a slug is hiding in a tiny hole in a potato.
The slug is attracted and killed by the pellets, leaving the rest of your crop unharmed. However, I’ve been told this may constitute a health risk and be a misuse of pesticides! Scattering slug pellets on the ground around your potato crop is OK but popping a few in a sack with them has not been assessed and checked and studied for safety.
So only following this tip when storing potatoes if you’re the sort of risk-taking daredevil I am.