I approach a creek like this:
Say I start in an area that I've confirmed gold, even just a speck or two...
I pick a spot as a central area and move out in a small radius from that point and down repeating the process till I have a large diameter hole a foot or two or three feet deep or more.
I examine the material as best as possible in each layer and removing all large rock/slabs that I run into. Then scoop the loose material and sluice.
I see where I am digging and how the gold appears in the inspection matting. I can tell which direction to dig on the appearance of the matting.
It's really a combination of material and inspection while processing. The inspection is a big part. I can tell dig left, right, or more down... You will see the bigger gold as it won't go far in the sluice.
Dredging and Highbanking inspection is much harder when dealing with such fine material. This is why I prefer sluicing and using hand suckers to get to what the shovel can't.
It's easier to decide the pay layers and path... just my 2 grains worth.
How do you work a creek?