I am enjoying the current threads on nucs, and I thought I'd start another one. After watching Mike Palmers nuc vimeos and going into my third year of overwinter in nucs. First year survival 1 out of 2. Second year 9 out of 9, Third year (this year) I am going into winter with 18. Clearly I am a relative novice, but I have learned a few things. Here are some tips/observations from my experiences feel free to add more.
1. You can't have enough nuc boxes, and spare frames in the spring. Unless you are planning to sell them you will need to have boxes on hand to super them up quickly.
http://s1110.beta.photobucket.com/us...tml?sort=6&o=0

2. If you keep your nucs on stands it is useful to make the stand twice as wide as the number of nucs you might keep on it. This allows you pretty good access to the middle ones. This one is a pain to work on. I made it to high, and it is an ergonomic nightmare trying to access the center nucs.
http://s1110.beta.photobucket.com/us...ml?sort=6&o=17

This one is better, it is knee high, and I can reach the center boxes quite easily.
http://s1110.beta.photobucket.com/us...ml?sort=6&o=13

3. Od Frank cleats - his contribution to my beekeeping - they are cleats cut with a 20 degree angle to them; The beauty of them is that as you lift them gravity pulls them into you fingertips and you don't feel as though they are going to fall. The green boxes have them. All the new nucs I am make from now on will have them.
http://s1110.beta.photobucket.com/us...ml?sort=6&o=14

4. I have given up on wooden lids. A 2 inch piece of styroam, and a feed bag inner cover is all that's needed.
http://s1110.beta.photobucket.com/us...ml?sort=6&o=10

5. I use 2 pieces of wood at the bottom of the nucs, and leave a gap of about 3/8 inch for them to drag the dead out. This can easily be closed off. I also reduce the hole in the side of the nuc for winter with a piece of plastic wine cork. A frost ring on the sub zero days is confirmation of life. This reduction is also useful when you initiate the nuc and don't want it robbed out.
http://s1110.beta.photobucket.com/us...ml?sort=6&o=48

6. My method to establish a nuc is to place a 2 frames of brood with a cell, usually either a swarm cell or a Mel Disselkoen OTS cell in a 5 frame box with a frame of honey and a drawn or new frame in a 5 frame box. I let it mate, and start laying. When it is established I add another 5 frame box and raise up a frame of brood into the second box. My goal is to get he cell in the box by the first or second week of June. By fall successfully mated queens are leading colonies that have filled both boxes. I give one gallon of Fumigillan to knock down the nosema and don't have to add much more unless the colonies have been started much later.

Last year I was overwhelmed by bees. This year, if winter is kind and I am lucky, I plan on selling half of the nucs or the tail will be wagging the dog again.