I remember many years ago, when I went to use a batch of grass seed that had been stored badly and subsequently spoiled by mice.
It looked okay but it didn't have a hope, it was virtually all husk.
I now store it in a sealed glass jar, so the mice can only window shop!,
The best piece of advice I can think of, is buy a seed to suit the situation you have ie shady, hard wearing, fine lawn etc...
Keep it well watered until established, it only has to dry out once and its curtains.