A couple of things:
When going through any gravelly or technical bit, try and see where other tire marks are. This is a good indication of which line to pick.

If the gravel you're referring to is anything like the pea gravel we have here in Western Australia here are a few tips:
Don't brake through it as it'll slow you down anyways.
If you're fishtailing, keep pedalling!!!...
Move your body weight around a smidgen bit to get traction