What worked for us while training was a harness with front attachment: if the dog starts pulling, it pulls itself around towards you, so you can get his attention and start over. Furthermore, we found out over time that when we walk the dogs, it's THEIR walk and they can sniff around as they like, on a long leash. When we need to go somewhere, we take the leash short, and by now they understand that this means walking nicely next to us. Maybe not by the book, but it works for all of us.
If you can, try fresh food: raw meat, soft bones, cooked vegetables, eggs, chewing stuff like tendons, cartilage. Our Lela was a muncher with kibble but when we changed to raw, she became a little wolf, really into food. And despite what vets say, I hold fresh food healthier than kibble.
Some good advice already here, and remember that you have to figure out what works for YOUR dog and YOURSELF - part of the magic of having a dog I guess (or kids). Our first pup, when in puberty could bite hard, too. We found that sound or verbal commands did not work (for dog and ourselves). We took to body language, standing firm (Yang in Chinese terms, putting some energy pressure, but not too much), silently, turned towards the dog, and turning with her movements, so she knew we were actively involved in the scene. As soon as she got it and stopped, we would go soft (Yin) again and turn away to take away the pressure. It took patience and practice, but we learned a lot about how these non-verbal interactions work and what makes our miss Lela tick. We still prefer - whenever possible - body language over verbal commands.
Agree with Debra. To add: our Lela has the same issues to a lesser extent. Recently we took her to a holostic therapist who looked at her from a TCM-perspective (Traditional Chinese Medicine), and without knowing the dog or the question, she nailed the issue instantly. TCM works with the elements - Lela is a Water-dog (basic emotion = fear); if Water is out of balance, the element that is supported by Water, Wood, becomes weaker. The Wood emotion is anger. Add both, and you get a 'fear biter'. To a certain extent you can compensate the issue with sensible behaviour (see reply Debra).
@nathanyodavis Well, another life, yes, whether it's normal remains to be seen. Many, even dog lovers/owners, find basenjis strange creatures and the way they move around the house (as in couch, table, bed) difficult to appreciate. As long as you realise you have entered a universe where different laws apply and new possibilities arise around the corner every day, you'll be fine.