This Is One Of The Easiest Joints To Tape When You Know How

Don't be in a rush. Don't try to coat it all at once.

Emped the paper tape first in some drywall compound.

Don't be in a hurry and try and second coat both sides of the corner at the same time.

Coat one side, let it dry. Then the next day coat the second side and let it dry.

Watch this video and see exactly how it's done.