In the German Swiss school of cheese making (as opposed to the French Swiss) pressing is very important, and cheesemakers are absolutely insistent that the cheeses be pressed very very well, and very very uniformly. A well formed loaf is an essential, and you must ensure that everything is well knit, and there are no surface imperfections when you take the cheese out of the press.
Now, there are many other schools of thought aside from how I was taught. I am curious to hear some of your thoughts and ideas on the subject.
But first, here's how I learned it.
The first rule is that you try and approximate the pressing weight so that it is equal to 8 times the weight of the cheese you are pressing (if you are pressing a 5 pound wheel, you need a 40 pound pressing weight) This gets up there a bit when we are pressing 30 to 100 pound wheels of cheese. (I need a press that applies about 280 to 300 pounds of force at the pressing stack)
A lot of people use a lot more force than this. But they also press their cheeses for a shorter amount of time.
Another important factor is that during the first several hours of pressing, the cheese must be covered so that it will retain the temperature necessary for knitting the curd. Some people press a small cheese under warm whey. The technique I use is to have the cheese, form, and pressing plates (the Järb form we use doesn't have followers, but rather a big flat board that is much wider than the form. The form is adjustable) are all wrapped in a heavy towel or something like that.
Then timing is important. The curd is well kneaded into the form (this is important, you don't just slap it in and hope for the best) and pressed out by hand to expel some loose whey. Then it is put in the press for 5 minutes, then 10 minutes, 20 minutes, 40 minutes, 1 hour, 2 hour, etc. until it is left overnight, and put into brine the following morning.
Another importqnt step to the formation of a nice wheel is that every time the cheese is flipped, the flaps around the edges where it seeped out from around the form are trimmed off, and after the final pressing a small cutting tool is used to bevel all of the edges. This helps a lot in washing later on. The trimmings we call 'Chäs Schnitte' and they are eaten right away.
We press in the cloth. It is important that the cloth be pulled tightly every time and carefully folded so that you will not leave cloth lines in the cheese.