Remember that the virus can already be spread by people not yet showing symptoms, or so mild ones that they are not correctly identified. So you need to be careful not to spread it always, even without symptoms.
What everyone needs to do
Keep at least 1.5m distance to other people, preferably 3m. Since the transmission is mostly via droplets from breathing, especially coughs and sneezes, they will fall down within this distance. There was a case where a passenger in a bus infected other people sitting 4.5m away, and also another person entering the bus 30min later, while some people closer by got lucky and were not infected. This clearly demonstrates that you should be taking extra care in enclosed spaces, where longer stay durations will saturate the air more with virus particles.
Regularly wash your hands with soap, or alcohol based disinfectant if not available. The virus can stay viable for up to 72 hours on surfaces, especially steel and plastics, and you can pick it up with your hands and then spread it to your face. Wash them before leaving the house, after coming back home, and often while outside. Remember to open any doors on your way to the hand basin before leaving the house, you don’t want to contaminate them when coming back home. If you are worried about a package being contaminated, you can let it rest somewhere for three days, after which the virus will be deactivated.
Also regular washing will irritate your skin, so do not forget to care for your hands. An alternative could be water with ozone mixed in.
Do not touch your face. Easier said that done. But make sure when you are outside your home. It helps to clean your face before leaving the house, as it reduces irritations that might trigger you to touch your face.
Wear a simple face mask. Masks do not protect you very much, but even a mask made of cotton will reduce the droplets you are spreading. They are most helpful to reduce community spread. Cotton masks do not work for long, they start to lose effectiveness already after half an hour, and should be replaced after one hour. For some background, see this Medium post by Sui Hang.
Avoid close contact with many different people. You might need to see some people to get through a longer lockdown, but we ideally want to be split into a lot of small, separate groups to prevent the virus spreading far. Putting together a small friends group, where everyone agrees to see only people within this group is pretty reasonable. But keep in mind that this needs to include everyone sharing a single home, so two friends with family would already be a group of 8, and making them larger is not really helpful.
What we need to do as a society
Organize widespread testing. We probably need to test around 100 people for every fresh case to find everyone infected, and to isolate them. This will mean 10 million or more tests daily for the entire world to control it. Without it we can never be sure who is clean of the virus, and cannot remove the lockdown.
Much improved contact tracing. We need to use the tracing abilities a modern phone can give us to quickly locate contacts, without needing a lot of man power. We can use both Bluetooth for automated contact lists, or GPS for time/location matching.
Closing down public transport, because it causes many people to be in close contact. We should be able to provide fast ebikes as an alternative.
Support people that cannot do their jobs because of the shutdown. This is a temporary demand shock, which does not change the underlying viability of the business once the lockdown is no longer needed. We have enough man power to keep everyone fed, so we can afford to keep them fed well. This will also mean that we should freeze payments for capital that temporarily cannot utilized because of lockdowns. Not only the businesses currently not having any demand, but also the capital owner need to make sacrifices to get through this situation.
Why did it get so bad?
We lost many opportunities to limit the spread of the virus thanks to incompetence and also poisonous politics.
When the virus started last year in Wuhan, local doctors sounded the alarm, but the communist party violently suppressed it, so that when they finally admitted to it, we probably already had 1000s infected.
The WHO was way too late in acknowledging that there is human to human transmission. Taiwan was already informing the WHO about it on 31.12.2019, while WHO still repeated China’s insistence that there wasn’t on 14.1.2020. And the poisonous way China is treating Taiwan also meant that Taiwan could not warn the world.
Then all countries not having experienced SARS did not understand the severity of the situation, even with the example of exponential growth and the severe lockdown in place in China. They for way too long considered it just a bad flu, didn’t grasp that a doubling time of 3 days means 1000 times more cases within a month, and didn’t take China serious, seeing the lockdown as a crude tool deployed by a backwater, instead of an indication of how serious COVID-19 is.
They also did (and still do) not grasp that a disease that is quite similar to influenza can spread quite a while undetected unless you are testing very aggressively. So all travel warnings came way too late.
The endgame
Mortality seems to rise with age, leaving people below 50 with a worst case mortality of 1%, and maybe 5% with permanent health damage. This is still awful, but it is low enough that societies will not collapse.
Also there is the paradox of Japan: Even though the country does not have a lockdown, limited testing and contact tracing, corona is not tearing though the country. About the only precaution seems to be widespread wearing of face masks.