Starting off with a simple folding nylon ID carrier. It's about the same size as a typical wallet, but no long slot to store paper money. It's kept clean looking, nothing a 'bad guy' could use to learn anything about you, except you are not giving away any personal information without a fight.

One simple change I liked and have done myself is to turn all your cards around. You know what's in your wallet, and what order they are in. no need to show the world more than you want to. There are security cameras and other types of technology that could allow someone to see into your wallet, But also simple low tech methods to get information from you like simply looking over your shoulder. What insurance you use, what kinds of drivers license you have (how old you are) and other things can be obtained with a quick glance. For example in Arizona people under 21 have a vertical Drivers License, while over 21 gets a standard horizontal license. 

What bank you use, where you shop, clubs you belong to, and even places you go can all be broadcast to strangers when you thumb through your wallet in front of them looking for something. Simply turning your cards around can prevent this.  I also fold my larger bills inside the wallet and keep the smaller bills folded in a front pocket as I'll explain further.

Some smaller paper items (checks, insurance, hunting license, etc) are kept folded inside a pocket in this wallet design, again kept from prying eyes

 

Small bills are kept folded in a front pocket. In case being alert and aware of your surroundings doesn't work and you are confronted with a thief or group of 'bad guys', having a few dollars to use as a distraction is worth a lot more than the bills might be worth. Throw the bills one way and run in the opposite direction.

 

I made copies of the cards and IDs in my wallet, in case it's ever lost or stolen, I'll have a quick reference with the card numbers, etc. I did both front and back in high quality