In think 3 things are essential:
The first is being able to draw/channel energy and use this to spell your intent and bring about your desired result. Power to your spells.
The second is to know that you are a Witch and have confidence in your abilities.
The third is to have an open mind, both consciously and also open your psychic mind through meditation.
After this go with whatever your crooked path takes you, but make time to sit outside both in day and night and listen. More will come to you that way than you can even imagine!
So my foundational basics are focussed on mindset and energy. If you can't channel energy or draw on the web of Wyrd then in my opinion you are not a Witch.
Great post and I agree on all your points.