Byakuren:
1st spellcard
3rd spell card
4th noncard
5th and 6th spellcard
1st spell is just simply dodging. Perhaps use some vertical movements to pass through openings of the smaller bullets while following the gap of the glowing ones.
It's probably more important to pay attention to the small bullets than the glowing ones.
3rd spell... practise some more and don't panic when dodging the curve lasers I guess...
5th spell is static, just keep practising.
Don't attemp to follow Byakuren when she's doing horizontal movements, stay on either the left/right side if you know which side she's stop moving at. You'll be doing most of the damage when she's resting or doing vertical movements. Beware of the charge up animation when she's at the bottom-left though.
6th spell is again, practising.
If you see a gap formed, rush through it without second thoughts, especially in the later waves.