Skills

There are a number of different skills that Aim Lab can help you practice. Some of the more important ones are

Precision
Precision is how clustered your shots are; how close together are they? Traditionally this is measured as a distance between all of your shots. In Aim Lab this has been simplified somewhat and is an average measure of how far from the center of the targets you are when you hit them. Dead center is better, obviously.

Some of the best modes for improving precision are microshot and spidershot. By selecting the 'precision' game type you'll be presented with targets that shrink and grow based on how precise your aim is. They will last quite a while so keep things slow and focus on hitting the exact middle of each target.

Accuracy
More straightforward than precision, accuracy is simple a measure of how frequently you hit the targets. Again, microshot and spidershot are great options for improving accuracy. While the 'precision' game types aren't necessarily "better" for improving accuracy, they offer the added benefit of being able to practice precision at the same time and so are often recommended as the best place to start.

Speed
Is often thought of purely as reaction time, which is a fairly ill-defined concept itself. For our purposes we're going to think of speed as "how quickly were you able to hit the target". The standing advice for how best to increase one's speed is to focus on other things. With practice, speed will naturally develop.

While this is true, most challenges have a 'speed' type which can be helpful if one wishes to specifically focus on speed. In this type the targets will stay available for decreasing and increasing amounts of time depending on how well you're doing.

Something to keep in mind with this type of practice in Aim Lab: the reaction time you see at the end of the stage is indicative of how long the targets were on the screen - not how long it took you to hit them. This is very important when using speed modes because, even missing entirely appears to give a good reaction time at the end.

Tracking
Tracking is the ability to hit a moving target, ideally multiple times in a row. This is the most challenging skill to develop but also one of the most valuable. In game targets don't tend to just sit there and let you shoot them.

Because it is such a complex skill there are many different mode for practicing different components of it. As a general recommendation however, motionshot is a great place to start. Other modes will help you bridge the gap between motionshot and freetrack. Also, freetrack can be configured in custom games to move slower. This can be another great tool but take care to manage your own progression. Too easy or too challenging and you'll learn less than you otherwise could.

Flicking
Flicking is the ability to re-target nearly instantaneously. It seems fairly magical because things will be moving more rapidly, during the flick, than humans are capable of tracking. In practice, this skill is about muscle memory and speed. Eventually experienced players simply know how far they need to move their mouse in order to target what they want to, no matter where on the screen that target starts. There is no other way to reach certain levels of speed than flicking from target to target.

Counter Strafing
Counter strafing is strafing around in the opposite direction that your opponent is strafing. If you see them moving right across your field of view, you strafe left. While not an aiming skill, per se, counter strafing is extremely important because it increases the difficulty of hitting for both of you. You're increasing the skill floor necessary for either of you to hit the other.

Freetrack, ninjatrack, and blinkshot can all be used to practice counter strafing. Remember, it will make them all more challenging to hit. This is exactly what you want. If it's harder for you to hit them, it will be harder for your opponent to hit you.