Blue Suit Glitch
The blue suit glitch describes the phenomenon in which Samus is in a constant state of blue suit.
The blue suit state normally occurs when Samus has achieved enough running speed (or more accurately, "once the boost counter has incremented four times" as explained on TASVideos), and normally only lasts until Samus ceases forward movement or ceases other means of temporarily maintaining it.
The blue suit glitch will last until either dash is activated with forward movement, or until the shinespark from the blue suit is used. The effects of blue suit can also be removed by submerging Samus in sand, or by pausing and unpausing the game while Speed Booster is not equipped, or has been unequipped.
All methods of the blue suit glitch involve interrupting a shinespark before it has crashed - crashed is defined in this context as "ceased by colliding with a solid surface".
Below are a number of different ways to perform the blue suit glitch. With the exception of the elevator transition method, all of these can be performed strictly inbounds.
The most common way to generate a blue suit is by having Draygon perish while Samus is shinesparking and has yet to crash.
Draygon does not need to be killed by the shinespark, Draygon merely needs to die while Samus is in the middle of a shinespark. This is because Draygon's death forces Samus into a standing pose, and this forced pose change will interrupt whatever pose Samus is currently in, even if that pose is an active shinespark - and if that pose is an active shinespark, then a blue suit will be given to Samus.
The primary reason why blue suit is occasionally not gained from killing Draygon while in an active shinespark is because blue suit will not be gained if the shinespark was performed after running forward, but without turning around before activating. Basically, if any speed is maintained before activating the shinespark, it will prevent the blue suit glitch from occurring. To avoid this, either avoid holding the dash button when you jump to shinespark Draygon, or perform a turnaround in midair before activating the shinespark so that any previous speed is removed.
The only instance in which the above will not hold true is if the shinespark's flight begins on the frame after it is activated in midair. (ex. up or angle up is pressed (to activate shinespark), then jump and an applicable direction are pressed on the frame after)
One way to tell if the shinespark was performed with maintained speed is if the shinespark has any echoes behind it during its flight. If it does not, then it means speed was maintained before performing it. To put it simply, a lack of echoes will mean a lack of blue suit.
Another way to gain blue suit from Draygon is to have Draygon grab Samus the moment a shinespark is activated. This is most commonly seen in Reverse Boss Order speedruns.
If you have enough energy upon leaving Draygon's chamber with the blue suit, you can use it to shinespark back across the Colosseum without stopping short of the door. Having low energy after Draygon perishes may warrant waiting on Draygon's drops (for potential energy drops) for better utilization of the blue suit.
A blue suit can be obtained while acquiring a suit upgrade. Varia Suit is the primary candidate due to the flat open space that exists in Kraid's Room that can be used to charge a shinespark; however, it is possible to acquire it via Gravity Suit, despite the area before the suit not being conducive to charging a shinespark.
With X-Ray Scope
Charge a shinespark in Kraid's Room, then enter Varia Suit Room. Shoot the capsule open, then switch to X-Ray Scope. Spinjump over the suit, then press angle up right before coming in contact with it. Doing so will activate the shinespark at the same time Varia Suit is collected. During the suit upgrade cutscene, hold run and hold either left or right while X-Ray Scope is selected.
Information originally provided by this pastebin.
Without X-Ray Scope
This can be achieved by using a Bomb Jump.
This could also be achieved with Grapple Beam if a Grapple block existed appropriately within the room of the suit upgrade.
Crystal Flashing can interrupt a shinespark. This is also known as performing a "sparkflash."
The Super Metroid's stun that occurs when Samus reaches 01 energy can interrupt a shinespark.
Mother Brain's rainbow beam can interrupt a shinespark.
Depending on the timing of the shinespark, the blue suit glitch may not occur, but will instead act as a standup glitch.
The cinematic Ridley performs on Ceres Station, which knocks Samus back, can interrupt a shinespark.
Similar to generating a shinespark suit by utilizing "Reserve Mode", a blue suit can be generated by having the Reserve Tank automatic refill interrupt a shinespark that occurs during "Reserve Mode."
By utilizing "X-Mode", a shinespark can be interrupted by releasing the dash button to disable the X-Ray Scope, thereby interrupting the shinespark that takes place during the mode.
Elevator transitions can interrupt a shinespark. The only way to accomplish this is by shinesparking into a transition block (out of bounds) that corresponds to a transition involving an elevator. Usually, doing so will also cause graphical distortion to some degree.
The example below, which takes place at the 51 minute mark, provides both console and emulator game feeds, with the emulator feed involving a hitbox viewer to display the out of bounds.
If you unmorph from a speedball while holding angle up and/or angle down, Samus will retain the blue suit so long as an angle button is held, at which point, you can jump forward while retaining the effects of blue suit. Alternatively, you can hold angle up or angle down as you crouch to charge a shinespark, and wait out the 180 shinespark timer frames. This is typically referred to as a "temporary blue suit."
The temporary blue suit will disappear when Samus lands from a jump, unless Samus soft morphs on the ground after jumping forward and immediately unmorphs while holding angle up and/or angle down again.
The temporary blue suit will disappear if Samus turns around, unless she turns around while utilizing the X-Ray Scope.
By being conscious of the above, a temporary blue suit can be carried indefinitely.