Use appropriate difficulty but better too easy than too hard. Make the navigation more important than the physical difficulty. Test the skill of the competitor, not his luck. Courses should be fun. White and Yellow should not get feet wet.
Beginners are equally important people.
The time it takes to complete courses is more important than the length. White, Yellow, and Orange courses should not share legs. Every leg on Orange, Brown, Green, Red, and Blue should have route choices except short legs used for positional purposes. Direct line by compass should only rarely be the best way to go. Streamers should be used on White and Yellow whenever there can be confusion.