Comment on “Spell Research Woes”

Imagine a player going about the final phase of spell research, i.e. in your example, the step where they've gotten the people, the location, the lab, and the ingredients they judge important, and now they're mixing things together and trying to get successful combinations or pull of rituals. How would you as DM indicate that they are on the right track? What does "smart" play look like here for the player?

Thanks.