Build A Dirt Bike Track

Here is how to build a proper dirt track.

Steps

Plan out your track before you start building and draw blueprints if needed. You need some jumps, whoops, and berms. Think realistically on what you can really do. Making the blueprints is like being an architect. What's plausible and what isn't? Would a triangle be better here since they're the most stable? Think about what can hold up what.
For the jumps, build small and pack the dirt every time new dirt is added.
For the whoops, dig into the ground instead of piling dirt. This is to help create easier sections.
For the berms, pile dirt around a corner and ride over it until the dirt is packed. Try to include some ruts to the inside of the corner.
Test it. Try adding weight to things before you go whirling circles on your ramp.

Try building your track obstacles after a slight rain so that the dirt will solidify and give you less waiting time.
Ruts in corners are more permanent when they are made in mud. Riding in the mud is more dangerous and it does not take much speed or torque to rip in a new rut.
Build a track that will challenge you, but be careful not to go too far outside of your riding skill. Start small and test before building up anything.