Israel is probably a valid example to look to.
We'll probably see similar attacks here as what Israel has coped with for decades, including civilian sniper attacks, kick-burglary-style home-invasion shootings, car bombs, suicide bombers, mortar attacks on schools and other high-density targets (think: sporting events, political rallies, parades), as well as various attempts to poison our water supplies chemically (e.g. ricin, cyanide) and infect our food supply biologically (e.g. anthrax, smallpox).
In addition we'll probably get hit by a few train derailments and highway-bridge collapses.
Done in the right way, your local infrastructure could be paralyzed for up to two weeks.
Simply insure that you have two weeks worth of food and water sealed in your home, office, or location in which you spend any sizeable portion of your time. Depending upon the type of attack, its affects, and our response (e.g. a no-leave-the-house quarantine in the case of a smallpox attack), you want to be able to handle the disruption with a minimum of muss and fuss.
More able-bodied types should probably consider taking adequate precautions for the home-invasion and sniper scnearios, as well as at least being aware of what one should do (e.g. offense or defense) in the case of a near-by mortar attack.
Can you heat your home for two weeks if the power and gas is cut off? It's worth mulling over now before the real fun starts.
Sadly, no enemy is dumb-enough to attempt a full-scale ground assault on sovereign American soil, so the odds of you being in a firefight of any substance are wildly remote (which bites because I could use the target practice).
But the other scenarios ARE ALREADY being played out in Israel, so it isn't much of a stretch to figure that they will try to bring them to bear on the Great Satan at some point in the future.
Not that it will amount to much, mind you, but they'll probably try all of the above, and one of the best defenses against all of those tactics is simply to have their "possibilities" of happening in your mind already so that any or all of them don't come as a complete and total surprise to you.
For instance, answer the question of "fight or flee" now, NOT when you see a herd of people either running down your streets or huddling in your airport terminal.
We've probably already seen most, if not all, of what they can and will do. Just look over to Israel. Every terrorist tactic can be successfully dealt with by the population at large, of course, but any of us who get caught in the fringes may actually have to take some actions on our own in order to be in as good shape as our society at large...