This article is based on the Grand Prix Legends wiki article, with some ACRL / sim specific tweaks.
This includes race day qualifying and pre-quali.
Stay out of the way of drivers who are on flying laps when you're on an out lap, or any other non-useful qualifying lap for that matter. With a full field the track can get crowded. It can be hard to find the space to complete a clean flying lap sometimes. It's all the worse if people who are on an out lap try to ‘race’ those who are trying to complete a clean flying lap. Be a sport. Let others complete their flying laps as cleanly as possible.
Also if you have spoiled the lap you’re on, by spinning, a really bad section or whatever, then also consider staying out of the way of others for the remainder of your non-useful lap.
Exit the pits carefully. Check your relatives, using whatever app the sim provides, to see if there is traffic approaching, and wait for a big enough gap. Exiting the pits does not give you any rights, and you should apply all the same care you should with any other track rejoin. During qulai, those on track have right of way, it is your responsibility to stay out of their way.
Some tracks are worse than others when it comes to a clean track entrance manoeuvre. You can leave the pits at Monza at full acceleration and drive adjacent to the main track for a few hundred yards before actually needing to move onto the track proper. This gives you lots of time to check your mirrors for approaching cars. On the other hand, the pit exit at Watkins Glen leads almost directly onto the racing line of a high speed sliding corner. There, for example, you need to be very careful not to interfere with someone on a flying lap.
Get off the track and out of the way ASAP if your car is non functional. If you crash heavily, run out of fuel, whatever, so that you’re on the track but not moving or moving very slowly for where you are, then move off the track as quickly as you can. If necessary, teleport to pits, even if this ends your race. Treat this as a matter of urgency, as if every fraction of a second counts, a it often does. Your race may be done but others are still trying to compete as best they can. Running into your stationary or slowly moving vehicle will not make their day. At the very least get away from the racing line, and do it with all haste.
Of course there may be some circumstance where a damaged car might still be capable of affording some benefit to its driver. E.g. Damage from a crash on the last corner on the last lap may still leave a car able to limp across the line for a beneficial result. An out of fuel car may still be able to roll a long way to cross the line. A damaged but still running car or engine may still be able to carry you to some points. Common sense has to prevail of course, and no one can expert you not to do everything reasonable to enhance your own result. But, if your current situation is not served by staying on the track, then please get off, and get off as fast as you can.
Show Yourself In Their Mirrors
To state the obvious, if the driver in front of you can’t see you then don’t be surprised if they crash into you, or cut you off so you can’t avoid crashing into them. As much as you can, show yourself in the mirrors of the car in front before making a move. While each sim, car and individual setup can have different blind spots, you should have a reasonable idea from your own experience where their blind spots are.
Of course once you decide to overtake a car you have to drive into their blind spots. But even then, if they get a good view of what your movements are immediately prior to your disappearing, they’ll have a much better idea of your probable position and likely immediate actions, and what they need to do to try to avoid contact. This is not quite the same as real life perhaps, but real life enjoys a much better visual range.
Never Run Into The Back of Someone
This is probably one of the silliest things one driver can do to another, but happens all the time. There’s few excuses here. If you are behind then you have the responsibility to drive in a manner that will not lead to you running into a car ahead. It doesn't matter if you're faster, think you have the right to be let by, are more talented, or think that all slower drivers should not hold up faster drivers. If you're behind someone then that's your tough luck. You have to earn your pass the same as anyone. However frustrated you may be, or whatever, it is your responsibility not to run into the car in front of you.
The most common excuse we all hear is "You braked too early". This is still your fault - if you haven't followed someone for long enough to know where their brake points are, you have to anticipate these possibilities and drive accordingly. Until you are confident you know where their brake points are, lift a little earlier, brake a little earlier than you normally would.
If you have messed up and you've tried everything, braking, gearing down, changing line, etc., but can see you're still going to collide with a car ahead, then you should drive your own car off the track, crashing yourself out of the race if necessary, if that's what it takes to avoid such a contact.
The in-front driver must not do malicious braking of course. I.e. Deliberately slowing down inappropriately to rattle a following driver. They are required to drive with all haste and due propriety. But while doing so within their limits they are entitled not to have to worry about whether a following driver will run into them.
Being able to follow another driver without running into then is something you have to learn to do. It often takes keen judgment and many times is not easy. You want to be as close as possible, to snatch a pass if a chance comes along, but you need to be far enough away to respond to the ahead driver's manoeuvres, evasively sometimes. It does take practice and it is a skill. But its an essential skill for successful enjoyable online racing. You can practice with friends, in non-serious races, or with the AI cars offline. Offline, pick a car that's slower than you and try to just hang on their tail for 10 laps or so without passing. You may surprise yourself at how much your skill in this area needs to be improved.
Avoid Close Racing When Not Necessary
Not only does very close driving give you very little time to react if the need arises, it also increases very much the likelihood of a netcode (lag) collision. In any online sim there is always a risk of registering a collision in close driving even without any perceivable contact , due to internet lag. The closer you are to another car the more likely this will happen. The general rule for the careful and respectful driver would be, not to unnecessarily drive too close to another, especially whenever there is no point. E.g. In situations where there is no possibility of passing anyway. You're asking for trouble if you do, even if you don't actually do anything wrong.
Use Clear Body Language
If someone is following you closely looking for a place to pass, and you kind of drift along with ambiguous movements about the track, or you sort of close the door but still leave the inside line half open, then you just might unintentionally lure the following car to try a pass that's only half on. Alternatively, if as soon as a following car gets anywhere near your rear quarter coming up to a corner, and while they are still in your mirrors, you make a firm and clear movement towards the inside line, and stick there, then they will know that your intentions are to close the door and drive the defensive inside line. Such a clear defensive move will leave them in no doubt not to try a risky inside pass.
This is just one case. There are others. The thing is ... Always try to convey a clear message by your driving style so that surrounding drivers get a very good idea about your intentions. Body language used well can be almost as clear as having indicators on your car.
Practice the Other Lines Before You Have to Use Them
If the first time you have ever tried driving around the outside of a certain corner is in a frantic race situation when you're racing toe to toe with someone, then you'll be in unfamiliar territory in the middle of a high stress precision driving situation. A bad place to be. Before a race comes up, just try doing a few laps of the circuit hugging the left-hand-side of the road all the way around and then do a few hugging the right-hand-side. At the very least do 1 or 2 laps against each side of the road. You'll be surprised at how much less likely you are to crash while trying to hold road position if you are at least a little familiar with how the outer and inner lines feel.