<questions about finishing drywall corners (inside) with paper tape
The last few times I've done this, I've used preformed paper covered
inside corner pieces, and they are *way* easier to finish than regular
paper tape. It's a metal (I've seen plastic too) piece, bent to
slightly greater than 90 degrees, and covered with paper. You apply
mud to the corner, then press in this piece and embedded it into the
mud. Apply a thin coat of mud over top of the paper, and smooth with
corner trowel. Because of the paper, the mud sticks very well.
From then on, you don't have to fuss with the actual corner, and just
finish the two sides as if they were flat joints. It took me a couple
to get the hang of it, but the end result is better than any corner I
ever did with tape.
You can also attach the piece with special spray adhesive, which is
even easier. Round here, both Lowes and Home Depot carry the pieces.
The also come in outside corners, which are easier than the metal type
too. Make sure you get the right one, inside vs outside, because the
angles are different, one more than 90, t'other less than 90.