[quectophoton]

After all this time I'm not going to trust a decoration.

When I'm connecting an USB cable horizontally I always think "hol up". So I always remember to plug it with the hole up.

When I'm connecting it vertically I think "hold right". So I know that if I want to hold it right, I have to put the hole right.

Has worked for me so far.

EDIT: Though "left" and "right" are more vague compared to "up" and "down", so connecting vertically assumes a specific "mental point of view". I'm just using one that's intuitive for me, but it might not work for everyone.