My biggest advice to new MCs is that “to do it, you have to do it” applies to read a sitch and read a person as well. You have to describe what your character is doing. I hear so many APs where the players are like “I read a sitch” or " I discern realities". But the player should describe what the PC is doing here.
And then the MC should never say their move out loud. So even when the MC answers the question, it should be a description of something physical that happens in the reality of the game, not handing them meta knowledge. Show, don’t tell.
“I look her in the eyes, watching for a hint of a lie” (Are they telling the truth)
“Her eyes are hard, and cold, and flat, no disassembling” (Yes)
“My eyes are darting back and forth as he talks, looking for any escape” (What’s my best escape route)
“Your eyes glide over it, so as to not bring attention to it, but the door behind Dremmer is slightly ajar”
Read a sitch is a little quantum-y. In game design terms, it allows the player to establish a piece of the fiction through their characters stats and random chance. When they roll well and look for an escape route, they’re creating an escape route in the fiction with dice.
This is story now play. The OSR generally has other agendas at play, which are also fun, but don’t really apply to PBtA.