If you notice someone is throwing you big points before the Called King is played, you may bet that this someone is your partner. The opponents may notice this too, and start throwing each other points. On the other hand, watch out for players who will dish the Declarer a few points early on, pretending to have the called King, thus leading the Declarer astray. If this ever happens, take the lead as soon as you can and then lead the Called King letting your partner know who you are.

Always be aware of whom is throwing who points!

Some players will Call a King only if they are completely void in that suit. Others will Call the King of clubs even if they are holding one or two clubs in their hands.

The important thing to remember is the player who holds whichever King you call will be your secret partner & if you or your partner lose that King, you both will be penalized 15 points.

You probably don't want to call clubs if you have 4 clubs in you hand: an opponent can play a Tarock and capture the Called King while you have to follow suit.

My advice is to find your comfort level and take a chance every now and then.