The king sits on his throne looking off to one side. The wand in his hand is still sprouting leaves, the back of the throne is decorated with lions and salamanders, and a small salamander sits at his feet. The King of Wands is someone who sees the whole picture and sets the direction — the way of deciding and bringing people along.
It could be you or someone around you. The manager who ends a long meeting with 'let's go this way'. The friend who starts a company and gathers people to it. You, who somehow always end up making the call on family matters. Rather than handling every detail, this person decides where things are going, and the decision carries weight.
Reversed, it points two ways. One is high-handedness: certainty that has tipped into not hearing anyone, deciding alone and expecting everyone to follow. The other is haste. Someone whose strength was quick decisions starts pushing through without checking, and it goes wrong. People rarely argue then; they quietly drift away.
Ask whether you can explain your decision, with reasons, to the people it affects. If you can, you are leading. If all that is left is 'just do as I say', you are ruling.
Reading the King as 'someone who has already made it' misses the image. The wand is still putting out leaves, which means he is still starting things. This is not a king who guards his seat but one who keeps widening the board.
With the Emperor, decisiveness gains structure and the plans last. With the Knight of Wands, there is plenty of heat and not much brake, so pair each decision with at least one check.