The simple fact that may seem obvious to some, is that the more your enemy, whomever that is, knows about you...the easier it is for them to compromise your situation.
Some critical parts of OPSEC are simply maintaining a low profile so to speak, never divulging information like you phone number, address, social security number, health issues, security situation (weapons, alarms, deterrents). One key way to do this is to adopt a moniker as most bloggers in this area have. There have been many instances where I specifically have been lax but I do try. Let's face it is easier to maintain OPSEC if you don't do something like write a blog on a daily basis.
Some simple things you can do to maintain OPSEC are:
1.) Get an unpublished phone number
2.) Never give out your address; this can be accomplished by getting a PO Box.
3.) Never talk about your survival preps with anyone you don't explicitly trust.
4.) Never talk about your protective/defensive measures (such as weapons, ammunition, etc.)
5.) Always try and maintain a low profile, don't be boisterous, flashy, etc.
6.) Blend in with the community - everyone remembers the guy who lives in small town USA and has a Mohawk and cross dresses.
7.) Have throw away email accounts and use them with everyone you don't trust.
8.) Never give your social security number out to anyone.
9.) Never talk about your finances to anyone.
10.) Never tell anyone your plans, except with those you absolutely trust.
BONUS - Never take what the government says at face value - there is ALWAYS and ulterior motive.
OPSEC should be a part of your overall plan to keep yourself, your family, and your resources safe when the situation deteriorates and dictates action.
Let me know some of your suggestions for maintaining OPSEC.
...that is all.