1️⃣ start with the ball on the hip: this way the ball is protected and away from the defender + it will make your jab fake much bigger.
2️⃣ shoulders over knees: try to always be lower than the defender. This way defender automaticly will give you more space, cause if he comes closer you can easily beat him shoulder to hip. .
3️⃣ shoulder fake: most important part in the jab is bringing your shoulder into the fake to really sell it.