Learn Italian: Avessi seguito il mio intuito, avrei evitato un errore fatale. - Had I followed my intuition, I would have avoided a fatal mistake.

In formal or literary Italian, you can drop se in a hypothetical clause. When you do this, you put the verb first, similar to the English structure "Had I followed..." instead of "If I had followed...". This is only done with the imperfect or pluperfect subjunctive.

Since avessi can mean "I had" or "you had", how do we know who the subject is here?

The subjunctive form avessi is exactly the same for the first person (I) and second person (you). In this sentence, the possessive adjective mio in il mio intuito (my intuition) is the clue that the speaker is talking about themselves.

Why does the second part of the sentence use avrei evitato instead of another subjunctive verb?

This is a Type 3 conditional, which talks about an impossible past (something that didn't happen). The condition part (the "if" clause) takes the pluperfect subjunctive (avessi seguito), but the result part always takes the past conditional (avrei evitato). This matches the English structure "had I done X, I would have done Y."

Is there a difference between intuito and intuizione?

Yes, though they are closely related. Intuito refers to the general instinct or sixth sense (intuition as a personal trait), which fits perfectly here. Un'intuizione typically refers to a specific, sudden idea or insight, like a flash of inspiration.