The military has considered camouflage for a long time. The things that give you away, and lead to getting shot, are typically movement, light, shine, noise and outline. For zombies, we can add smell. Simply locking your doors and not attending to anything else in the way of camo will lead to a crowd of zoms milling around your place, attracting more zombies, lower property values and making it difficult to get out of your own driveway.
Additionally, excessively aggressive security measures will attract the attention of non-zombie scavengers. Look too prosperous, and some will ask to join you, and perhaps not entirely politely.
So, what to do?
First, physical barriers. Start by having solid doors, sturdy windows and using the locks on the doors. Windows on the ground floor must be locked, those on upper floors can be openable, but must be blocked to a small opening to prevent entry. Then make a perimeter. If the outbreak is shufflers, you won’t have to be too heavy-handed here. Enough of a physical barrier, starting as far out as you can to slow and re-direct them, will do. A picket fence without gaps in it would be enough to re-direct the walkers. If the outbreak is fast-movers, you’ll need as hard and secure a barrier set as you can manage, and that will not be possible very far out. Here, a six-foot high chain-link fence, motion detectors and fields of fire might be necessary.
Second, don’t attract attention. That means even if you do have power, you need blackout curtains. No showing light at night, even if it is just candles and lanterns. No loud music. No generators, unless you can make the noise un-noticed or un-reachable. A generator in the empty, adjacent house next door, with the muffler pointed up the chimney, will be very quiet. Open fires might not attract attention, depending on just how much stuff is regularly on fire, but the smells of food cooking are different than rubbish burning — or at least I hope so. If your “cooking” doesn’t smell any better than burning rubbish, you have a new problem set. That will be harder to disguise, but some smells are more pronounced than others. We all know when the local grill master fires up for the first time in the spring. We can smell his efforts for blocks. So resist the temptation to roast a pig on a spit over a great big open fire.
One of the things that comes with any civilization is noise. Even a quiet residential neighborhood is noisy. Take all the noise away, and the silence becomes noticeable. Use that noise to your advantage. The old rock-in-a-can trick works, but you can do better. Rig a wind chime so the wind doesn’t cause it to chime, but an opening gate does. Trip wires also. If you have three or four different wind chimes, you will be able to tell where the entry is by the tone of the chimes. No power, no batteries, simple and cheap. They can, however, be relatively negated by live, as opposed to undead, intruders.
Last, no barrier is an actual barrier unless you can ensure two things: You can observe it, and you can bring it under fire. You need to have safe observation points from which you can see all exterior walls of your dwelling. You cannot permit blind spots, which are mischief waiting to happen. Also, your perimeter has to be in sight. If you always have the fence gates closed, and on taking your hourly look, see a gate open, you know there’s a problem. If you can’t see that gate, and it is open, you have no way of knowing if the yard is even safe enough to go out for more firewood or water.
This isn’t rocket science, but it is unforgiving.