How to Increase in Knitting Using Backwards Loop Cast On (BLCO)

Backwards Loop Cast On increases, or e-loops, are great to use instead of M1 lifted increases when you want to add a stitch between columns without affecting the tension of the stitches to either side or below.
BLCO is especially useful in colourwork (because it doesn't interfere with the colors of the other stitches) and in mitten thumb gussets (because the tension is so even and pretty).
This video shows how to make Backwards Loops that lean left or right (for mirrored increases), using both continental and English knitting techniques, and how to read the stitches and troubleshoot them.
Their common knitting pattern abbreviation is BLCO, BLCO-L, and BLCO-R.