+1 on the balance idea, which applies to most anything. On the bike is no different in any position - just takes some practice to get comfortable with a different position to the point it is second nature.

I use a variety of positions to stretch the legs (rotate between which pedal is at the bottom, then stand and lower the heel), I use the pedal horizontal and lift the bum up slightly - squeeze quads a little against front of seat and top tube for stability - for downhill, aerodynamic position. For those sections of bumpy or wavey pavement I stand a little and pedal or coast in horizontal so arms and legs act like shock absorbers.

Having more positions gives you more options to adapt to a variety of conditions.