Really just classify as much as you can, to include picking rocks out.
I have a bunch of classifiers, and for cons, I will go 1/4", 8 mesh, 20 mesh, 50 mesh and 100 mesh. That leaves five different sets to pan with a sixth larger one that I can run the metal detector over. That is a lot of work, but that will make the lighter sands go to one side of the pan more than others. You can get creative with a classifier and use a strainer or colander. All the stuff I find is less than 8 mesh and very few +20 mesh pieces.
Oils from the hand can make the gold float, but a drop of FINISH (C) JET DRY (C) you'd add in the dishwasher will prevent that. Honestly the gold that floats away from the oils in the hand is tiny and you're chasing less than a penny worth of gold. OK for a hobby and learning, but not practical if you hit a pay streak.
I also suggest becoming good at it prior to buying something to help. I'm not a fan of the blue bowl. Just seems like it does not move enough material and still needs to be classified. I like a Spiral wheel because it can process a scoop at a time, but I still classified and needed a bit of pay dirt to make it worth the effort. The gold cube is good. That will take concentrates and take it down to a cup or two of super concentrates. Even better is a reverse helix trommel, but those can be pricey. That produces a better super-concentrate that can be run across a miller board like the black magic. Other than a Super concentrate, a miller table does not move enough to make it worth it. A miller table only takes half teaspoon at a time is not a lot.
At least those are my opinions after having bought and used all the above except a blue bowl.