When going slow steer by pushing, to turn left push with your right and letting off a bit of pressure with your left, and visa-versa to go right. Pushing on the handle bars steadys your bike when going slower than the gyroscopic effect of your wheels. This prevents the wibbly-wobblies.
Don't use your front brake in low traction areas like dust and mud, it will lock up quick and there is a great potential to have the wheel turn either left or right and throw you off.