This one is for the girlies with pre-cut layers in their hair. Simply braid or tie back the longer pieces of your hair, leaving out the top layers that are your ideal bob length. Then apply clip-in hair extensions to the back of your head, leaving the top-half of your hair exposed and style as needed.
LullaBellz's Thick 14" 1 Piece Blow Dry Wavy Clip-in Hair Extensions (£14) come in a range of natural hair colours and are perfect for creating a voluminous bob. For coily, curly hair try Ruka Hair's Think Kink Clip-Ins (£160) or their Cork Crew Clip-Ins (£160) for a looser, defined curl.