It sometimes, but not reliably, runs with the wind and waves. It can change with depth and tide, and it can be hard to spot from the surface. To identify it at the surface, look for ripples around stationary objects like the anchor chain or a buoy, or notice which way kelp lies. Superimpose these directional clues on your mental image of the dive site. Draw arrows on your slate for sun, wave direction and surface current.
Reciprocal courses are return routes.
Add these, and an arrow for magnetic north, to the sketch on your slate. Keep in mind, though, that the purpose of drawing the sketch is, as much as anything, to fix the image in your mind. Your goal is to navigate without relying on it. Next, plan your dive. Decide on a logical route through the dive site and back to the boat, then superimpose it on your mental image of the area.