You might have heard about the immense technical skill required to even play a game in the Super Smash Bros. series. While some basic tech is required for some advanced gameplay, it's not too hard to learn and apply. Practicing these skills for just less than an hour every day can give you a huge boost over your friends. Note that some of these techs are not applicable to all games in the series.
Tech - Short Hop - Fastfall - L-Cancel - Dashdance - Wavedash - Directional Influence (DI)
A tech can be performed within 20 frames of hitting a surface while tumbling by pressing L or R. By teching, you are put in a short period of invulnerability, and perform an action similar to spotdodge, or if you hold left or right, roll. If you mistime your tech input, you won’t be able to tech for 40 frames. This technique is useful for escaping combos, as missed techs are highly punishable.
A short hop is performed when you release the jump button before you exit the jumpsquat state (in it, you look like you’re crouching). Each character has a different jumpsquat length, and so timing short hops varies for each character. This technique is useful as it reduces the commitment you make to a jump, leaving yourself vulnerable in the air for less time.
A fastfall is performed by pressing down at the peak of any airborne state. This means you can fastfall after jumping, after being hit upwards, after dropping from a platform, or after walking off a platform. This technique is very useful in conjunction with short hops as you can further reduce your commitment to jumping by landing faster. Additionally, changing fastfall timings is important for mixing up aerials on shield.
L-cancelling is performed by pressing L or R within 7 frames before landing after performing an aerial attack. It halves the amount of lag you would have from landing after performing an aerial attack, which allows you to act faster.
A dashdance is performed by quickly flicking the control stick from side to side, keeping your character in the dash state, and never entering the run state. By dashdancing, you are able to bait out attacks and punish the opponent. Note that with some characters, the amount of time to be able to switch direction increases, allowing for easier baits.
Wavedashing is performed by airdodging into the ground after jumping. The distance you travel is dependent on your character and the angle at which you airdodge, with angles closer to the horizontal yielding greater distances. Note that maximum distance wavedashes are not necessarily the best, as wavedashing is more often used to micro-space oneself, which requires precise distances. It can also be used to act out of a jump cancel (such as jumping out of shield or out of shine).
DI is performed by holding the control stick in a direction when hitlag ends (the control stick can still be held before this) after you get hit. Depending on the angle at which you hold the stick, it will influence the trajectory you travel at. The maximum amount of influence possible is by holding the control stick perpendicularly to the trajectory. If an attack were to send you horizontally, in this case, DI is maximised holding up or down.
Two types of DI exist, survival DI and combo DI. To maximize chances of survival when being hit by a strong attack, DI in a manner that would send you closest to the upwards corners of the stage. Note that using survival DI when being comboed with weak moves is not effective as this pops your character in the air to continue being comboed. In this case, combo DI should be used, holding away from the opponent to make it as hard as possible to continue the combo.