There are several different combinations u can have. However the best is to have 1 of everything besides barracks and cottages in your first city. You should have several of both barracks and cottages. In my own opinion, i say that barracks are more important then cottages, because once you get into the higher levels of KoC, you need to quickly make troops. However, it is also important to have cottages so you can actually make troops and have workers for you resource fields. So it would be best to have about 10-12 barracks and 7-9 cottages. For your resource fields, you should have 3-5 sawmills and mines, 1 quarry, and rest farms. In the beginning you can have more sawmills, mines, and quarries, but in the end this is how it should end up. Once all your buildings are lvl 9 (or 10 if u are using divine inspirations) and your wall defenses maxed, there is little need for stone, therefore 1 should give you plenty. Wood and ore is important for building archers, so you still need sawmills and mines. Food is the most important because you need to feed your troops. And once all your research reaches lvl 9 (or 10) you can deconstruct your workshop and blacksmith because you will not need either in the future. (I am not sure if you can deconstruct your lab and keep all your research, so it is probably a good idea just to keep 1.)
In your 2nd and 3rd cities, you will not need a lab (if you already have lvl 9-10 on all your research) or a blacksmith, so there is no point in building those 2. Again you want to make many barracks and cottages. The field should be the same as the first, and once you get your wall to lvl 9 (or 10) you can deconstruct your workshop.