To fasten off I prefer the Invisible Fasten Off. It is a fastening method that looks just like a stitch, and helps make it impossible to tell where the fasten off was made.
Double Crochet Decrease (dc2dec) (dc2tog)
How to decrease double crochet (My way)
How to make the Extended Double Crochet (edc)
The extended double crochet is a variation of the double crochet. This is a very easy and fun stitch. What are you waiting for, come on click :)