Most importantly - CHECK THE DEPTH and base so you know what you are in for.
Momentum is essential.
In deep mud, low 2nd or 3rd are probably best. Keep a steady pace and if possible, keep out of ruts. If you do get in the ruts it is probably better to stay there.
Moving your wheels slightly from side to side can also help with traction, especially on muddy hill climbs.
In the unfortunate event of becoming stuck, try self-recovery first using Treds or similar, before opting for the winch.
There are a multitude of websites available offering more information on this topic or alternatively, you can always check with our club driver development officer.