You need to work out what other stones are usually found with your target be it gold or gems , gold I would be looking for heavies like basalt etc , sapphires I would be looking for spinal and if your talking about creeks and rivers I would start with a inside bend just after the apex and hopefully behind a large rock or structure that would cause a dead zone in floods.
There's alot to learn on how gold and gems behave in floods and understanding that and being able to picture these movements when its not in flood will get you going.
Best thing is get a pan and test pan lots of spots thinking about what I've said and see what rocks you have left when your pans getting empty, these should be your heavies , gold and gems are both heavy and should be the last out of your pan, being heavy they won't be on the surface and you won't find them by walking along looking you need to dig and pan.