Applying mud drywall joint compound and tape to an inside corner is difficult because it typically involves blending three corners the intersection of two adjacent walls and the ceiling.
Mud and tape ceiling corners.
Hand taping inside corner.
To tape outside wall corners start by attaching a metal or plastic corner bead to the drywall corner.
1st coat always takes longer to dry.
For inside corners i prefer to use paper tape instead of fiberglass mesh tape because it is creased down the center and it s strong and easy to work.
Smear the compound down the wall completely covering the wall corner and corner bead.
The skill and care with which joint compound and tape is applied to drywall determines whether or not the finished wall will look good or bad.
I always like to use fast set joint compound to get it done faster.
Scoop some pre mixed joint compound onto a hawk then apply the compound to the wall corner with a 6 inch drywall knife.