Have you researched what the size of the gold is that was found in your current prospecting area? For example, if it's micron gold (flour gold) it's going to stay up high in the bars. It's going to waste a lot of your effort to dig down deep to find where the "pay" layer is in the gravel bar. Flour gold likes to drop out where there are fist-sized rocks or larger. It will be deposited in the top six inches generally.
As has been mentioned earlier, there are certain indicator minerals and rocks that run with the gold: black sand, garnets, ironstone (magnetite, hematite). When you find them you'll be close to the gold: to the right of it, to the left of it, slightly above it, or if there's no gold, you'll have a nice collection of black sand and garnets.
If the gold is coarse (good flakes to nuggets) that's when you'll want to dig down to hit bedrock or a solid clay layer (or some other solid layer that won't let the gold pass through) to look for the bigger gold. If the gold is coarse, the size of the rocks you'll be looking for will change as well. Where coarse gold drops out (in runs or bars), the rocks will be watermelon sized or larger. Bigger rocks and bigger gold really like to travel together.
There's lots more to it than that, but that will get you started.
Read all you can. Visit as many online sites as you can to read and ask questions. (If you want to, you can pop over to my main thread to read some tips on chasing the gold:
http://www.treasurenet.com/forums/metal-detecting-gold/69-bedrock-gold-mysteries.html
Welcome to the forum and welcome to the passion.
All the best,
Lanny