Three years ago, I could never find a queen. It didn't matter how big the colony was, or how long I looked. When I wanted to find her, I couldn't. When we weren't looking, invariably I would spot her.
I started a couple nucs beside the house in early May two summers back, and let them raise queens. By the time they got queens built, nucs were not strong at all, just a couple frames of bees. The queens were easy to find in those boxes. I made a point of using those nucs to get good at finding her. At least once a week, I went thru them, hunting down the queen, and persisted till I found her. Over the summer they grew, and by the end of the summer, one of them was in a 3 high stack of 5 frames, and one in a 2 high stack of 10 frames. I learned a lot by persisting and hunting her down at least once a week in both of them. It was actually easier to find her after the colonies got bigger, which I attribute to persistent practise. It is a little difficult to quantify exactly what I'm looking for, I've tried to explain it to my wife as we go thru a hive last summer, and didn't do to well. But, ever since then, I can open any of our hives, and as I pull up frames, just looking at them I can tell if it's a good candidate for finding her.
Last summer, and again this spring, I've noticed a trend. More often that not, working my way across the brood nest, where I find her is on the first frame of honey / pollen on the far side from where I started. Particularily this spring while they are building up. I'm not sure if it's because she's on the edge of the nest looking for more room to lay, or if it's because she has been running from me as I pull frames. Probably the latter. I am not using smoke when I am determined to find her, and my suit is buttoned up tight. Sometimes they get angry, sometimes they dont.
I think what made this a lot easier for me, by using the same two nucs growing into full size colonies for the exercise, every week for a whole summer, I learned a lot about those two colonies, how they built out and where the bees were putting various things in the hive. Over time, I also figured out where each of the two queens liked to hide when I started pulling things apart. But, what is the real big thing for me now, when I walk up to a hive with the express intent to find a queen, I'm confident I can find her. Personally, I think that's 3/4 of the battle. If you walk up to the hive thinking 'I sure hope I can find her today', you've already lost the battle. If you walk up to the hive thinking 'I wonder which frame she's on today, will be interesting to find out', with no doubts you will find out, you are 3/4 of the way to success before you pop the lid.
If you have watched the videos from the National Honey Show, then you saw the piece about the cloaking device. It's sooooo true. If you _think_ you saw her on a frame, then she vanished, she is probably there. You have to look away, blink, then slowly start scanning that area of the frame again. Invariably, she will pop out of the herd of bees. Another thing I've noticed over time, once you do spot her, it seems that suddenly all the nurse bees move away, and there she is, plain as day in the open.
Lots of folks say, dont spend a lot of time inside your hives, it'll disturb the bees to much. Particularily in a case like yours Janne, you have a bunch of colonies out back, and started more from packages this spring. Pick one or two of the fresh start packages, and just resign yourself to the fact they aren't going to be productive honey hives this year, instead they are going to be learning tools. Open them up once a week, sometimes twice. Go thru them frame by frame, make a point of finding that queen every time you open them up. By the end of the summer, you will have learned a truckload about what's happening inside those hives, and you will be able to tell what's happening in the rest of them, by simply popping the cover and lifting one frame. And by the end of August, you'll be able to walk up to any of them, large or small, and feel confident that if you must find the queen, it's a 5 minute job most of the time. That confidence is 3/4 of the battle.