Through the years I have identified recurring rules that underly most of my "bugs", "failures", "mishaps" and other blunders.

Rule 1 : If you connect it to the power supply, it works better.

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Rule 2  If you connect it with the right polarity, it works even better.

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You could argue "it goes without saying" but it goes better when you say it ;-)

Please comment and contribute with your own "golden rules" :-D