minimal clutter, optimizations to note sprites to mitigate note ghosting, clear spacing between notes
minimal clutter - No fancy flashy lights or useless stage lines. Black background, a judgment line, and moving notes is all you need.
optimizations to note sprites to mitigate note ghosting - This has more to do with how much you can up the scroll speed before it becomes hard to read jack patterns due to notes duplicating due to poor refresh rates. Arrows/Orbs are best for this kind of thing rather than bars, but it sacrifices the next thing I'm gonna mention.
clear spacing between notes - My skin are bars, with spaces in between them column to column. It causes some ghosting, but I'd like to think a clear advantage it has over arrows/orbs is that I can better read unsnapped spacing. It's hard to see whether arrows/orbs are a few pixels apart as they are moving across screen. With bars you can judge how far they are spaced apart because the note edges may not align at top or bottom. Finally, the spacing column to column horizontally creates a lighter feel when tapping to the notes.
So minimal clutter is a definite one, but from there it depends on how fast you want your scroll speed to be and what kind of patterns you want to be better at.
