Always lock your aircraft

Don't leave keys in unattended aircraft

Use secondary lock or aircraft disabler if available

Lock hangar when unattended

Security related TFRs can be implemented with little or no notice

Always  check NOTAMS that apply to your route prior to flight

If unsure of information in a NOTAM, do not assume, alwayts check with your FSS by calling 1-800-WX-BRIEF

FAA Website for TFRs
http://tfr.faa.gov/tfr2/list.html

Monitor 121.5 if able when operating in a TFR

Familiarize yourself with military/law enforcement intercept procedures

Remain on ATC assigned transponder code unless instructed by Air Traffic Control

Aircraft with unusual modifications or activity

Pilots that appear to be under the control of others

Unfamiliar persons loitering around the field

Suspicious lease or rental requests of aircraft

Anyone making threats

Unusual suspicious activities or circumstances