First, let them pass in the initial choice of the game.
On the train, totally reject what your parents did, then ask Blaise to sit with you. Go in Blaise’s carriage, state intentions to work, then tell Freddie and Gonzales to pull themselves together.
Once in school, in Miss Dalca’s class, choose the option about not worrying about the lower classes and focusing on your own ambitions. You’ll need to be more traditional for this to work, so I recommend (in addition to those choices already stated) not helping the porter when on the train platform, brushing up on the books, wondering why Gonzales didn’t neaten up and asking Gonzales where they are from. That’s if you want to believe in ghosts, which I usually do. If you don’t, you can afford to be less traditional prior to this.
Back to school actions, ask Blaise to share your bed or give them the bed. Then accept the apology unreservedly and ask Lady Renaldt not to be too harsh on them.
Later on, get sent to the mines, tell Blaise you missed them, make an acerbic comment (Flair), be supportive (Accomodating), let them fight Karson, ask if they think Karson really doesn’t regret it, take both Blaise and whichever teacher is in the mines with you, then confess your feelings and tell them ‘You wish’.
I was able to get a Blaise relationship of 80 with this combination of choices, though there are others that may work equally well.
In other news, I’ve found myself unable to get the Inked achievement by getting a tattoo with Max and Delacroix. Anyone else experiencing this, or am I just going mad?