That's like a very common thing with manga/manhwa lol. Many artist basically draw the same face on everyone. You kinda have to learn a new language to notice the differences.
Look at the hair (color/tint, root color, does it part on the left/right side, does it stick up in specific areas, is it straight or slightly wavy, messy or more slicked back). In this, the two blond guys can be distinguished by the love interest having darkee shade and shorter, more slicked back hair.
Then there's the mole-thing (often the "pretty" characters typically have a very specifically placed mole somewhere on the face). Not relevant here though, i think
Piercing is another. The "brother" has a piercing in his ear.
Eyebrows (curved/straight, thick/thin, rotation). I think you can distinguish the main character from the last dark haired we saw by the eyebrows. The other guy had sort of straighter eyebrows rotated a bit downwards by the temple ? But it was hard to spot any difference there since we saw very little.
Eyes (wide/slanted, long/shorter, do they rotate a certain way - one thing I have noticed is that crazy/stalker characters tend to have eyes that rotate downwards by the temple lol)
There's probably other things that i cannot recall.
Omg thank you. It is partly also due to the fact that i cant distinguish people in real life neither. But your observation is really helpful
Yeah, i'm totally face blind as well haha
Does anyone have a problem with distinguishing the characters from others ? I cant figure out who is who sometimes