For your mom - scrapbook, frame, candle, bath set (lotions, soaps), spa giftcard, or something that she likes. For your dad - tie, golf balls, sports items, giftcards to lunch or sports places. And to both of them, a clay pot you make and glaze. Those are some ideas. Good luck and merry Christmas!
I get my dad beef jerky sometimes. This year I got him new tools. My mom loves doughnuts and last year I got her some cookie sheets. Depends on interests. If your dad likes hunting/fishing get him a new camo hat. Adjust.