Crease the paper pattern on the line you're going to sew and place the pattern face up on the wrong side of fabric #1. (I wasn't really sewing on this--just used it for an example.)
Fold the paper back with the crease at least 1/4" from the edge of fabric #1.
Place fabric #2 wrong side up, butting it up against the edge of fabric #1.
Open the pattern and ensure that it totally fits on fabric #2 with plenty of room (at least 1/4" seams all around.)
Fold the pattern back again. With an erasable or washable ink, make a small mark in the exact same spot on fabric #1 and fabric #2 (see the little blue line?)
Carefully place both pieces right sides together matching the mark. Open the pattern and sew on the paper piecing line. It opens up at the right angle every time for me--love it!
Disclaimer: As noted above I'm an amateur, not a pro, at paper piecing.
If this works for you, GREAT! Whoohoo!
If it doesn't work for you, pretend you never saw my method
of working the angles and go back to using your seam ripper over
and over and over and over again.