Okay, take this for what it's worth. Our plane has a speed card velcro'd to the visor with rpm/configuration/speed for doing approaches. Some of those are for 90kts flaps up, 90kts with 10° flaps as well as other speeds that include descent rates as well as straight and level. So set the power and configuration and you've got your 90 kts.
Next, I took a map of Oshkosh and figured out distances and altitudes for each point in the downwind/base/final for each runway and dot. I only did 27 and 18 since they're the ones with tight downwind/base/final maneuvering. From that, I drew a map and marked each point with a nominal altitude/speed/descent I needed to be at. I put all that information into index cards and then laminated them.
Okay, so the last thing I should be is heads down reading index cards in the pattern at KOSH. So, while it's quiet (days/night before, or coming up from south and I hear the ATIS), I use them to review what the numbers should be. However, I always fly with someone else, so if I'm PF, I have them make sure I'm where I should be while they're also looking for traffic and verifying radio calls with me. If I'm the passenger, then I'm helping the pilot know where he should be.
But also, I practice before going to Oshkosh and make sure I'm comfortable with what needs to be done to fly safely at KOSH.
Actually, last year we came up from East Troy (cheap gas!!), straight to Green Lake, then joined the conga line just as they released the hold around Green Lake and there was one plane in front of us and a large gap in front of him. He struggled with the distinction between a road and railroad tracks, but he kept his speed up. He went to 27 and we got 36, so it was just a normal long left base, then final, with no one in front of us. So I didn't need the cards (just followed the NOTAM) and flew normally.
I know some folks have such a practiced eye and are one with the plane and the atmosphere, so they can float in like a seagull to the admiring applause of the spectators, but I do what I can to make it an science as well as an art.