Keep doing the 1/2's, but make sure its a late 1/2. When they can do that, have them land the 1/2, then do a jump 1/2 turn. When they are comfortable w/ that, have them do the full. If things get crazy, go back to the 1/2's. Patience is the key when teaching twisting... no spotting necesary.. do you hae apit or resi pit landing.