I am 9thOm, Om, Aum, or 9.
Save time after battle (enemy clear)
Remain still while closing post-battle screens. 12 frames are required for Katia to return stillness.
Comparison video:
Hold R when pressing A to close post-battle screens. This way, precise timing is not important. I like two thumb A button pressing for this.
Save time doing running/walking clip
Plains of Rowahl
Video reference:
Shown in video: Walk past large seam, rotate camera for easy stick posioning. Run straight into wall, slide left, position stick for stationary run toward area shown in video. Clip is faster to be done from left; left to right requires more precision on stick to be done quickly.
Bridge of Saravan
Video reference:
Shown in video: Run perpandicular to bridge wall, turn to run directly into bridge wall. Aim for empty space between two lines on bridge floor.This may cause instantaneous clip, although that is not the goal. Walk into bridge wall with stick at angle that does not slide quickly. Upon Katia falldown at seam, cease controller input. Tap gently to pseudo-step toward seam where Katia had falldown. If Katia moves across the seam once more, tap the other direction. Camera orientation causes tapping toward seam to have wider range of success from right-to-left. If tapping proves faulty, slide along wall toward seam, cease movement predictively when Katia is about to touch seam. This is akin to running into the seam and clipping instantaneously. If Katia stops before the seam, tap again as instructed prior.
Yyprek Mine
Video reference:
Shown in video: Run to corner of level, face North. Take 1-2 step with stick position North-NorthEast. Jitter occurs with stick position too close North, slide occurs with stick position too close East. Tapping stick to position (161, 154) is instantaneous clip. If Katia slides, run into corner and face North again. If Katia jitters, micro-adjust stick to be more Eastward.
Bernden
Video reference:
Shown in video: Walk to corner above seam. Walk into wall across seam. Threshold of walk must be close to run. Align Katia's left foot to dirt/black dots texture on ground as you walk into wall. Nano-adjust stick to slide slowest possible speed up to seam. Refer to video for detailed instruction.
Clip from above is possible, but it is too hard to teach 100% method like clip from below. Slide up slow from below seam value (180,155) is clip, (180, 156) is nano-adjustment to approach seam. Recommend using two hands to hold stick completely steady.
This concludes knowledge sharing. Memory expands, knowledge to share shall reflect. Future time.
Practice must be done to share greater efficiencies.
Community is welcome to observe: https://www.twitch.tv/9thom
Om
Wow, these videos are super helpful. How'd you figure all these out? I've had a lot of trouble with the Sarvan and Bernden clips specifically.
First, studied speedrunners. Second, studying game. I did test with angles, frame advance, save state. Did lots of notes, too. Doing more notes and studying tomorrow!
I have put Bernden notes here https://pastebin.com/vVWx0cTE
Not done with study Saravan. Sharing not finish notes 
Edit: Expand Saravan. Note is important, tap>walk because WIDE range walk angles. Is possible to run inside walk angle. Different from Plains of Rowahl, is possible to run/slide into wide SEAM. Difference caused by camera orientation (Katia orientation), seam shape, clip area. OK, still noting detail.
Yyprek mine note: 
"ONE FAST MOTION" 
faster than gif.
Cut out return to neutral frames in gif.
Example for not precise step clip (.25x speed)
Not done with study game. Not done Saravan, Yyprek, Bernden, Castles, Church, Ruh-Arok, Broch Black. Note for all level will be done.
