Years ago a friend of mine sent me this information. A lot of this information I found to be very helpful and have followed through on.
The next time you order checks have only your initials and last name put on them. If someone takes your checkbook, they will not know if you sign your checks with just your initials or your fist name, but your bank will know how you sign your checks.
When writing checks to pay on your credit card accounts, do not put the complete account number on the “for” line. Instead, just put the last four numbers. The credit card company knows the rest of the number, and anyone who might be handling your check as it passes through all the check processing channels won’t have access to it.
Never have your social security number printed on your checks.
Place the contents of your wallet on a photocopy machine. Do both sides of each license, credit card, etc. You will know what you had in your wallet and all of the account numbers and phone numbers to call and cancel should you lose your wallet. Keep the photocopy in a safe place. If you have a secure site where you keep your passwords (1Password for example) you could also store this information there. If your wallet is stolen you will have the toll free numbers and your card numbers handy so you know whom to call.
File a police report immediately in the jurisdiction where your credit cards etc were stolen.
Call the three national credit-reporting organizations immediately to place a fraud alert on your name and Social Security number. The alert means any company that checks your credit knows your information was stolen and they have to contact you by phone to authorize new credit.

It is important to be diligent and protect yourself! For more information on the credit reporting bureaus read more HERE.