The following is the Miller method for finding reclusive queens:
 
First, put queen excluders between all the brood chambers, put the hive back
together again, and come back in a week.   The queen will now be confined to
one box.
 
If you do not feel confident in your queen spotting ability, visit a local
observation hive and find the queen in that a couple of times.   Note how
many differences you can see between the queen and the other bees.
 
After the week is up, come back with a spare box.  Examine frames from your
colony.  The frames that have eggs and/or young brood in them are from the
box that has the queen in it.
 
Use as little smoke as possible, and in general disturb the colony as little
as possible during the queen hunt.  Also, if you have beekeeping friends, an
extra pair of eyes helps.
 
When you are done examining a frame from the box with the queen in it,  put
it in the spare box.  If you empty the original hive box without success,
that means you have passed over the queen.  Take the frames out of the spare
box, and examine them again as you put them back.
 
Queens are generally on frames with eggs/ young larvae in them.  Queens are
rarely on honey or nectar.
 
If you find the queen, then mark her, pull the queen excluders, reassemble
the hive, and you are back in business.
 
If you don't find the queen, reassemble the hive with the queen excluders,
and try again tomorrow.  You will know which box to look in.
 
If you suspect a queenless colony, put a frame of eggs from another colony in
the suspect colony and come back in a week.  Examine the frame.  If you find
queen cells on it, then the colony was queenless.
 
Good luck.
 
 
W. G, Miller
Gaithersburg, MD