Tips for mud I learned this past week...
When riding through a mud section with actual standing water/puddles in it, ride through the deepest section of the puddle, barring the occasional foot deep puddle this will be the fastest line, with the most firm smooth ground at the bottom. I had heard this tip before but forgot about it until this past race when I was following my team mate after he lapped me up into the puddle, then I saw his line and followed it. Soooo much faster.
In deep sections of thick sticky mud rather than shifting to an easier gear and trying to spin through it shift to a slightly harder gear, keep yourself planted in the seat and pedal, don't coast, and don't try to turn unless you have to. This will power you through the mud much faster and you will be more stable than standing and spinning.