10 Tips for a Better Bug Out Bag

In no particular order...

1. Make your bag urban friendly (ie: this as opposed to this).  You don't want to look like a threat or a lunatic.  You want to fly under the radar and look like any other urban commuter.
2. Don't overload your BOB, you may be carrying it a long ways.  With a 40l pack, you can walk for hours or days; with an 80l pack you can walk for an hour.  Only one.  If that.  (And I'm talking about the average person...plenty of mountaineering and military folks can hike for hours with a super heavy pack but for most people that isn't reasonable or even possible).
3. Get in the habit of putting the batteries in backwards in any electronics you are carrying (radio, flashlight, etc).  This will prevent the device from accidentally being turned on and draining the battery (just remember you did this so you don't check the item six months later and toss the battery thinking it doesn't work).
4. Make the items in your BOB do double or triple duty (alcohol wipes make an excellent fire starter, hand sanitizer, and wound cleaner; a condom can be, well, a condom, a tourniquet, and a water carrier).
5. Shop the Goodwill (and the $1 store and Walmart, etc).  You don't need a BOB with only REI-purchased high-dollar items.  Pay more for critical items (a knife, a firearm) and less for less critical items (clothing, matches, paracord, etc).
6. Layer your clothing.  You can pack less, lighter weight clothing if they are layerable instead of specialized clothing for each and every circumstance.
7. Make your BOB as versatile as possible.  You want a BOB that can be used for bugging out into the woods as well as spending a few nights at the hospital or in a hotel.  Many people pack their BOB like they are going on a 20 day mission in a war zone and that just isn't necessary.  You don't need every creature comfort, rather you need the basics to survive.
8. Dump the contents of your BOB out every six months and check all of the items for usefulness, check that the item still works (check the batteries, for example), check expiration dates on food, etc.
9. Take your BOB out for the weekend, live out of it in the woods, and see what works and what doesn't work.  Revamp your BOB as necessary. 
10. Make your BOB low key.  It shouldn't tell everyone that you are bugging out, it shouldn't scream "commando", it should be a small, lightweight bag full of insanely useful items to see you through a crisis.