I can just give you the tips I give parents...
Do you use the Hollister brand bags? They have the Preemie Pouch and then a newborn sized one. We have to use the preemie one a lot, and it kind of sucks because there's no way to get the stool out without either taking off the bag or cutting it. We like it when a kid is big enough to use the newborn size, since it has a luer lock port to remove stool easily.
We only change the bags if they're leaking. Once the bag is off, we just use warm water and a washcloth to clean around the stoma, unless it's really dirty then we'll use Cetaphil or something gentle like that. After it dries, we'll put on the new wafer. We like to make a "sample" with a hole the size of the stoma, so we just have to trace it on the new wafer and then cut it out. Once cut, I rub my hands together to make them really warm, then press the wafer between them to soften it up. A heel warmer or warm blanket works even better. Once softened, it's so much easier to form it to the baby's skin and not have any pockets or leaks, and seems to last much longer.
My trick to getting the bag to stick on the wafer - Stoma-adhesive paste. I never put it on the baby's skin, of course. I take a 10cc syringe and pull the plunger out, then I put the tube of paste against it and fill it with the gook. Put the plunger back on, and now I've got 10cc of paste that I can push out through the tip of the syringe in a nice, thin line. I pull off the adhesive tabs for the bag and then draw a thin line of paste all the way around, since the adhesive on those bags is not very strong. Then I press it onto the wafer and hold for a minute or two until it sets. I've had very good luck preventing leaks (and therefore frequent bag changes) with this method, as well as warming the wafer first.
We don't see much skin breakdown around the stoma unless there are frequent bag changes, or if people are cutting the hole too big so it's exposing the skin around the stoma to stool. That's why we make that sample one - much easier to trace a wafer that will fit than to guess how big the hole needs to be.