How to sign the letter T in ASL

A fist with the thumb tucked under the index finger, peeking out between the index and middle fingers.

Easy to confuse. A rests the thumb outside the fingers. N tucks the thumb under two fingers instead of one.

T is one of the six fisted letters - A, E, M, N, S, T - that differ only by where the thumb sits. You cannot check these on yourself, which is what the camera is for.