Signs, signs, everywhere the signs...

I keep reading all these books that tell me to watch for signs of the baby being hungry, tired or overstimulated. To be honest, I can barely figure out when she's hungry never mind overstimulated or tired. If she's yawning or rubbing her eyes, I figure that she's tired but other than that, it's really hard for me to tell. I know that rooting is a sign that she's hungry but this girl has a serious oral fixation and she roots all the time! As for the overstimulated part, other than crying, I wouldn't have a clue what overstimulation looks like. I thought that I would be better at figuring out what my baby wants but it's much harder to figure out than I thought.