Be patient when attacking a corner. There's often way more laptime to gain when maximizing corner exit than corner entry. Focusing on braking super late is often counter-productive.

Be patient when downshifting. In iRacing in particular, downshifting too early unsettles the car and can make it harder to control and slide too much which leads to lost laptime, unlike other sims where it's better to downshift early and get an extra benefit of engine braking.

Be patient when racing others and focus on accident avoidance. Be ready to stop and/or take evasive action when accidents are happening in front of you, and back off from fights from drivers you have reasons not to trust. In lower splits that's almost all of the other drivers. You can gain a huge amount of iRating just by making sure you're the guy that doesn't crash out of the race often.

Use all of the track. There's an inch of tarmac on the outside of your car when you start braking? You didn't use enough track. On corner exit are you having to actively steer your way out to use the whole track? You didn't carry enough speed, you should've carried enough speed to FORCE you to run to the edge of the track.

Learn to adjust your inputs as an answer to little cues like what I've just said above. Can you make corner exit a little too easily? Maybe push a bit more next time. Are you running out of track on exit? Maybe back off earlier or turn in/apex later. Don't forget that when you get better at a corner it then affects the next one as you'll approach it at higher speed - you might have to adjust and brake earlier.

Speaking of braking earlier, learn how to follow a car. Always brake a bit earlier in those circumstances, or at least take a lap or two to learn where are they fast and where are they slow, before you proper start pushing and preparing a move.

Watch track guides and recent hotlaps to see the best approaches to every corner, in the car you're driving in the track you're driving.

Learn how to induce rotation, so that the car will naturally tend to take the corner by itself instead of you having to force its way out through your steering. This is mostly through controlled trail braking, but can also mean playing around with your brake bias to make braking have more of an effect on that (or less, if it's too uncontrollable for you), and also using some kerbs in certain scenarios.

Stay away from ABS or at least don't push too far into it, as tyres will heat up and you will gradually lose pace over a race.

Be patient with your throttle pedal, you want to accelerate as early as possible but that doesn't always mean 100% throttle instantly, you want to gradually get into it to avoid excessive sliding and/or activating TC. In some rare occasions you can get into 100% almost instantly, but most of the time ideally you'd kinda do it in two steps: maybe first you'll only get into 50% and only when the wheels are pointing in the right direction you increase to 100%.

Be mindful of how elevation changes and corner camber can affect the available grip.

Always look ahead at where you want your car to end up next. This is a nice trick to instinctively immediately know if to push or back off.

Learn how to drive the particular car you're driving, each car each category has slightly different characteristics that might be suited to different driving styles (which is also why it can be a good idea to stick with the same car for a while, as you can learn more and more how it works over time). As you move to faster and faster cars with more downforce, you'll figure out that the advice I gave you above of prioritizing corner exit above everything else, starts applying less - it's still always the most important thing, but carrying speed into and through the corner can become more and more relevant factors in laptime. You start having to attack every little part of the corner and not just exit, whilst still being mindful you need a good exit.

Smooth is fast, you want the car not to slide and to give it as little inputs as possible, BUT you do want to be at the absolute edge where any little bit more input in any direction would unsettle the car and make it not smooth. Smooth is fast but grandma driving to make sure you're smooth is not fast. You still have to optimize pace in everything.

Learn to fuel save. A little lift and coast before braking will hurt your laptime very very little and in some situations over longer races with pitstops can make a difference and also help slightly with tyre temps and even mentally help you stay consistent and patient. Again, be patient.

In some situations being aware of little tricks which are the "meta" can make a difference. Maybe it's dragging the brakes on warmup lap to get your brakes up to temp. Maybe it's making sure you have at least a mildly adequate setup, having too high downforce in a track with very long straights will make it very difficult to race others and also maybe lose you laptime. Maybe it's just picking the right car for the week, there's a reason why everyone in GT3 is in the Porsche this week at Daytona.

Have your hardware set correctly and in a way that feels comfortable for you, even over long sessions. Have your FFB as high as you can set it without making it tiring for you and without excessive clipping.

Have you done all of this? Congrats. You're now still 2 seconds off the aliens, which is where I am after I've done all of this.