How much fertilizer?

[mascia]

Hey everyone,
I always follow the instructions when mixing fertilizer with water, and most times I opt for a more diluted solution, but how much should I use on each plant?

I've been pouring a small cup of the solution on each pot, which seemed fine, but today I watched a video from an experienced orchid grower and he used at least 4 times more fertilizer than me.

Considering most of the water will simply run through the drainage holes if I use a huge cup, does it make any difference? Is there a rule of thumb?