Taking care of a baby is at times very difficult and a lot of work. When caring for a baby for the first time it is very overwhelming. Babies are such fragile little beings. It is difficult at times to know what a baby wants when they are crying. It can be for a number of things from wanting to be played with, to hunger, to needing a diaper changed. It takes a lot of patience when caring for a baby. You can't expect them to calm down right away when you want them to and are trying to help them. It may take a while before you get to the cause of the crying.
There is not much you can do for a baby if they are a newborn, but to make them comfortable, feed and change them, and make sure they are clean. After a few months they start to notice more things and seem to cry more. They will then want to be played with and want you to talk and interact with them. Caring for a baby that is becoming more interactive starts to take more care. When that baby becomes bored, they may cry for attention. They need to be cleaned more. They also start to eat more, although they can go longer periods of time before letting you know they are hungry. Changing clothes from them spitting up or puke becomes a habit like having to change a diaper.
From my experience, it is easier said then actually done. Once someone has been put into the shoes of having to care for a baby they will never know what it actually takes. From being up every few hours, to finding out what the baby needs. At the same time you have to be calm have, have patience, and show the baby love and that you are there.