Talent is usually discernible from a long distance or with a small sample size. Even when a major director's work is a little undercooked and not quite successful, we can see the makings of a real filmmaker.
Here's a short called WHAT'S A NICE GIRL LIKE YOU DOING IN A PLACE LIKE THIS? made by 20 year old student Martin Scorsese in 1963. You can feel the humor of the time and place and you can also sense the assurance and gifts of its young writer/director. The camera movements and edits feel like prime post-TAXI DRIVER Scorsese and the pacing feels downright GOODFELLAS-ish.
It has a real Nichols and May feel to it, and an enthusiasm for every film technique the young director could master, which even at this early date, was a lot.