I've tried dozens of times and have only managed to do it once. It seems I have top hop on three dry koopa troopas in a row and use them to launch myself up.
I've watched this video demonstrating what to do a few times, but don't know what they're doing to get that last high jump. I can do the spin at the end, but usually miss it by one coin.
How do I get that second black coin?
Best Answer
Since you didn't ask "How do I get the second black coin in world 1-4 as Mario", the answer is simply:
Play as a character that has a higher overall jump than Mario: