1. Realize that a bug out bag is NOT a camping kit
-- in 98% of scenarios you are moving to a safer building; red cross shelter, hotel or relatives house. You are far more likely to need clean work shirts than an anti-zombie machete.**
2. Think in terms of multiple bags; one backpack with the essentials; one for camping gear, one for pets, one for family ( paperwork, photos, etc.)
3. You will likely be moving by car -- likely slowly, but by car. Is it ready?
4. Water is heavy - pack empty containers and add when needed.