I mostly focus on 4 things: hair (sometimes I included hairstyle), eyes, voice, and aura. Enough to set a character apart from the others and not too many to handle.
Let be honest, no one want to read a Great Wall of Text (unless it’s interesting), and many people in this forum don’t have English as their mother tongue (+ 1 reason to skip a text wall), but if you write too simple (like, in one sentence) then it leaves no impression. So don’t throw everything on player’s face, cut the appearance in parts and let the player read them slowly as the story goes on, in the end they will get the RO’s appearance in detail but don’t have to go continuously through a Great Wall of Text.
For example: A appear by saying something or interrupting a conversation - start describing how their voice sound (because that’s what you know first about them), when they enter PC’s eyesight you can say “a blond man with blue eyes” or just “a man/woman/person”, after they leave you can tell how they make the PC feels like. In future encounters and specific moments, you can start to describe other things in detail.
But every character has something special and things that separate them from others. So the introduction between each character will be different: a handsome man will make a strong first impression with his appearance, a frightening king has a strong aura that the only thing you remember is how scary he is, an assassin with a haunting voice that you can recognize everywhere,… So you don’t have to follow any sequence or formula, just choose the outstanding detail.
One of my favorite authors introduced her main character by only describing his aura in the first chapter, I must say it’s kinda unforgettable.
(Noted that this is a translation)
He begins the evening by eating.
He smiles again, as he circles around the long table, and his smile still lingers like white chiffon, no, it must have been a streak of red wine, faint and translucent.
He wears a napkin around his neck. Looking at the way the small silk embroidered with flowers meticulously caresses his neck will make others crave. People will go crazy. Everyone will have to talk about it while suppressing such greedy desires, to be rich, to be leisurely, to escape the mundane world, and to be courteous like that. Vulgar men will be riled up with envy, gossipy women will gossip about him again with ferocious admiration for his beauty and wealth. The ladies will tremble behind the fan or huddle behind each other at the sight of him, and the sons of the dukes will have to send many letters to befriend him.
P/s: If writing a wall of text is inevitable, at least make them interesting. Don’t just describe things, include some emotions (kinda hard for second-person perspective if the player has different emotions than what you write), some fun facts, sarcasm… or whatever. Just make sure you want to read that text wall after, because if even the author doesn’t want to read their wall of text then how can the player want to?