Back Loop & Front Loop

Back or front loop crochet (abbreviated as BL/BLO and FL/FLO). Remember as a rule of thumb: The loop closest to you is the front loop. It usually lies on the outside when you crochet three-dimensional bodies in spiral rounds. The loop further back, away from you, is the back loop. It lies usually on the inside when you crochet three-dimensional bodies in spiral rounds.

Working into which loop?

Crochet stitches are always worked through both loops of the next stitch(looks like a "V" on the stitch) unless the pattern tells you otherwise.

Working into Back Loop(abbreviated as BL/BLO)

The loop further back, away from you, is the back loop.

Working into Front Loop(abbreviated as FL/FLO)

The loop closest to you is the front loop.