Exactly. you need to be up close. Over time i've learnt to pick up more likely places to search. The more level places might be a good place to start. anything too steep will more likely not have river stone. then again you only need to find a small area if in gold country to perhaps hit good gold if its there, as finding the river stone is just the start.
around here its a bit easier as the lake was at various higher levels in the past. so going up tributaries of the lake you find where the gravels have settled when the rivers hit these old lake levels. where the gravels settled so did any gold. since the lake dropped the gold is in these areas or close by if its there in the river to start with.
I've come across some very likely ground to find nothing. there is always a trace of gold of course around here as its all gold country. there are also certain rocks that are heavier that will be good indicators too. as gold goes these are just that indictors. doesn't mean certain gold. its just that gold is obviuosly heavy, and these other rocks are heavy but not as much as the gold, so hopefully where gold have dropped out of the current the lighter heavies did too.
examples of indicators i've used are, magnetite, obviously, even made man iron items like bolts, nails, or bullets/lead, picks, all the metal type stuff. Schellite is another one. the rounded red schist stone is another. it depends of course what sort of country you are in for these to exist there.
WWW