Avoid leading unsupported aces in suits partner hasn't shown.
Following that advice worked very badly on this hand:
My 3♦ overcall is very marginal, but I was getting sick of doing little but passing and following suit by this stage. In the absence of anything from partner, lets try the top of sequence lead, that is usually a decent lead.
Not this time. Dummy wins, and three rounds of clubs follow, declarer pitching a heart. Even taking the finesse into my stiff king couldn't stop ten tricks for 22.9% to us.
I have to lead ace and another heart, then a third heart guarentees making the spade king, and we end up with a diamond trick, one down.
I'm not good enough to know when it is right to break these fundamental rules (guidelines).