King, queen, ten, and one small, in trumps.
Lead king.
Sooner or later, the leader will be marked with exactly four trumps originally, including queen, ten.
King, queen, and more than two small.
Lead queen.
If queen wins the trick, follow with fourth best remaining in hand (compare, lead from king, queen, ten, and more than one small, in trumps).
If queen forces ace, on the appearance of the king, the leader is marked with more than four originally.
In trumps, the same, holding seven trumps; with less than seven trumps, lead fourth best.