Source: Learning Points by Steve Moese & Mike Purcell for http://www.cincybridge.com/ 
Here is a classic.
1= Michaels Cue Bid – 55 Majors
2= Stopper for NT. Invitational +
LHO leads the 6. They are using 4th best leads.
Counting the Lead – Rule of 11 shows RHO has no higher than the 6!
Counting our HCP – Dummy has 13, Declarer has 14 for 27.
Counting our Tricks – After the lead, we have 8 tricks off the top. If the A is with LHO, we can lead low to Dummy’s K finessing the Ace. We have a 2-way finesse in s.
Counting a side suit – Since LHO’s bid shows 10 Major suit cards, LHO has only 3 cards in the minors. Let’s play on s to see how many s LHO has. Leading the A then K shows LHO follows to the 1 st 2 rounds of the suit. s are breaking 3-2.
LHO has room for only 1 card in their hand. So, play the A. If LHO does not play the Q, play the J from dummy finessing RHO for the Q. This way we can postpone the finesse in the danger suit.
Running off 10 tricks (2 s, 4s, 4s) will put pressure on LHO. They will likely discard to hold KJ A. If you keep AQ and 9, you can lead a at trick 11. That will force LHP to lead from their remaining KJ into your AQ. You managed to lose only one trick! Isn’t counting shape wonderful? You play so brilliantly!
DISCOVERY is a powerful strategy. Many successful declarers use discovery well. Discovery means playing side suits and watching for SHOWOUTS. Declarers can count exact hand patterns. Hand pattern alone does not guarantee finding a missing honor. Knowing the exact suit split allows a declarer to play with the odds rather than against them. You can also use discovery to learn who holds major honor cards.