Life with a newborn would be a lot easier if babies were born knowing how to talk. "Hey, mom! The temperature in here is a little warm. Can you turn down the thermostat? Also, there's a scratchy tag in my shirt; if you could cut it off so it's not wigging me out by irritating me in a weird place I can't reach or do anything about, that would be awesome. Oh, and I'm hungry. Thanks!" They can't say all that in words, but often a newborn will let you know you're doing well as their parent in their own little newborn ways.
Right as I gave birth to my son and heard him cry, I remember feeling so upset that anything was bothering him, and wanting to do anything to avoid hearing him sound so flustered and upset again. Of course, that's impossible. However, over time I did figure out how to "read" him so that we could keep his crying to a minimum. I figured out which little expressions and gestures meant he was getting hungry, so I could avoid his most desperate, hangry cries (and all the boob-clawing that followed. Ugh.). We discovered that he had a specific face he'd make when pooping, so we could get his diaper ASAP even if there was no noise or smell. (We also learned to wait a couple of minutes after seeing it to avoid getting pooped on while changing it.) Little by little, we figured out the whole parenting-a-newborn thing, and got pretty good at it, based on our son's happy reactions.
Of course, all babies are different, and babies who were born early and/or who have special needs may not do the same things, even though their parents are also doing an incredible job. But if you've got a full-term, typically-developing baby and you're wondering if they approve of your parenting, keep an eye out for any of the following signs: