Security comes in layers, so you could start with your environment to create a feeling of being watched and opportunity for neighbours to come to your aid. This has severe limits after SHTF, as police will be incapacitated and overrun, whilst neighbours will be scared even if they are alive and not injured or ill. Ideally, some neighbours will be part of your mutual aid group and ready to rumble.
You could start putting feelers out for mutual support group members, and generally harden the area, by asking police if you can launch a neighbourhood watch group.
Security means delay pending response force. You need guards indoors, on the perimeter and in the neighbourhood to deter and spot undesirables and neutralise them if they come too close, plus a response force for back up, which could be shared amongst a MAG.
Once the area becomes without rule of law (WROL) consider extending your CCTV with covert modules in the neighbourhood using mimicry and concealment. Looking at Allwan products for example, French police have used fake fuseboxes with cameras and hard disk recorders that attach to lampposts feeding off the street supply, drop cars with gimmicked accessories hiding cameras such as baby seats, headrests, mobile phone holders, vents for van roofs, and solar powered speed signs with memory card and 4G transmission. To give you further inspiration, Leonardo have helped police hide ANPR cameras in roof boxes and bumper grilles
You probably do not want to pretend your home is abandoned in an urban area as neighbours know it is not.
Do not let anyone see your gear coming in or rubbish from it coming out.
Turn up to soup kitchens to avoid looking well fed. For the same reason, keep some oversize clothes so you can go out looking like you have lost weight. Equally, only go out wearing yesterday’s dirty clothes and before you’ve washed and combed.
Acoustically insulate generators, use only stealth fires and black out windows if you have lights.
Apply the Art of War:
Use speed and deception.
Take food from the enemy.
The strongest never have to fight.
Sneak rather than attack if you have small numbers. Run and hide.
Defence is safer than attack.
Ensure your enemies fear harm & don’t expect gain. So only reveal non-ballistic defences when attackers arrive.
Unless you need to be invisible to reconnaissance, ensure you can be seen from all angles by passers-by. Buy a home that is overlooked by neighbours with a mix of property types to maximise the chance of somebody being home at any time of day. However, you must be able to watch the watchers. You do not want uncontrolled covered vantage points that you cannot see behind, like walls on other property or hills of trees facing you, especially transport nodes.
Look into drones as you can get models with half an hour battery which you could operate from away from your home to avoid giving away the location, to check out the area for threats after SHTF. But if you need to know who is coming in to town beyond that you need a radio network with friends or an unmanned aerial vehicle (UAV).
Do not ignore suspicions as, for example, most terror attacks happen after somebody saw something but dismissed it.
in cul-de-sacs with interconnecting paths or backing onto open land,
with public paths or parking to the rear (a complete no-no),
on busy main roads or through roads or cut-throughs,
on narrow or one way streets,
in isolated villages,
in concrete jungles,
in neighbourhoods not dominated by legitimate users or with no private zone,
that are obvious targets due to being seen from a distance or by having different lighting or appearance,
on ‘movement generator’ streets connecting major centres or near ‘out of scale’ facilities such as district supermarkets in the middle of an estate,
that do not have a field of fire all around if you have an armed response,
far from emergency services,
over 15 minutes from your response force such as a MAG,
that force you to travel on dodgy routes such as bridges or crime-riddled areas or past iconic structures or previous flashpoints,
adjoining an open space where a mob could gather.
Generally flats are bad news as your neighbours are too close, fire regs preclude decent security, your front door is hidden from passers-by, walls are often flimsy, and dark vandalised halls can breed contempt. Flats tend to come with stairs or lifts or underground car parks – all of which allow criminals to arrive, escape or operate unnoticed.
You could use a cliff, valley, river, forest or hostile vegetation as a deterrent perimeter.
A riverside property is bijou and makes access generally harder from one side, but is potentially a channel of drift and discrete avenue of attack. With the right money you could look into barriers (nets, barges or sunken obstacles) to create a threat zone you will defend, and beyond that patrol boats for a warning zone demarcated by markers (nets, barges, buoys, markers, boats or booms), or even electronic harbour security systems with sonar, radar and thermal cameras, but then you need a pier guard tower, so you need a lot of money and men.
Tactics are to put a screening/contact & escort boat out front in the warning zone to head off uncommitted adversaries, and to turn 90 degrees to the far side of adversaries who do not back off, so you stay out of the line of friendly fire. Put a tactical response boat behind that in the threat zone, which will line up with an adversary and come between them and the riverbank perimeter, and come dead in water to create a steady platform for fire. When the adversary defies warning, both your boats fire. Military use running gear entanglement net launchers.
Towed grappling hooks and stun grenades are swimmer countermeasures for the highest risk sites, backed up by lighting and sonar.