Two major things have helped to stop my gum recession:
- Learning how to brush right. No more super hard back and forth motion. Now I do small, light, circular motions (kind of like how an electric toothbrush works).
- Getting adequate vitamin C. I started supplementing with 500mg a day, on top of lots of C rich foods like broccoli and strawberries.
Other things that may have helped: oil pulling, flossing a few times a week, going paleo, becoming replete in pretty much every nutrient.
ETA: Oh also, sweet, hard fruits like apples and pears really seemed to aggravate the receding gums on my bottom front teeth. Could be a combination of the sweetness (feeding bacteria) and the pressure on my gums from biting into one. Every time I bit an apple, my bottom gums would start bleeding and they would look like they just got punched in the face.