If your dog is forging, wrapping around your leg, sitting crooked, or drifting wide in heel position, take a look at where you're delivering your reinforcement.
Reward placement in heeling matters. A lot.
Dogs are very good at figuring out where reinforcement happens, and they'll adjust their position to get themselves closer to that spot. If your treats are consistently delivered too far forward, your dog may start forging. If you're reaching across your body to feed, you may end up pulling your dog's front end toward you and pushing their rear end out. Even small changes in where and how you deliver reinforcement can make a big difference in your dog's heel position.
When I'm troubleshooting a heeling problem, reward placement is one of the first things I look at. Sometimes we spend a lot of time trying to fix the dog's position when the way we're reinforcing is actually contributing to the problem.