Even though I am a new chicken owner I do know a lot of Do's and Don'ts.
Ok so first the basics:

Water, Feed, Lock up at night
To explain that, obviouse why you need to feed and water, but locking up at night. When i first got my chickens, I didn't lock them up, but then they started to get eaten. So it's very important that you lock them up in the hen house, even if you don't think anything will be able to get them.
Leave them outside at night, small amounts of water given, and little amounts of food
Like I said above, it is a possibility for them to get eaten if they aren't locked up in the house at night. They need to always be able to get to water. You need to give them a good amount of food, if they chase you looking for more food, they obviously need to be given more food. If when you walk outside, they don't really bother you, then they are getting enough food.

Now to the less obvious Do's and Don'ts:
Put chicken wire or sement in your chicken coop, collect eggs daily, clean chicken coop weekly, seperate chicks by size
If you have an outside section in your chicken coop, put sement or chicken wire on the bottom of it so nothing can dig up into the coop. Then after you do one or the other cover it with and inch or two of dirt. Even though the eggs will still be ok to eat, it makes me feel beter to collect them daily, just for piece of mind. Also they don't get as "poopie." No one wants to eat "poopie" eggs. Some people find and article where you can just put enough shavings in the chicken coop to suck up all the wet-ness. Well you could do that, but it will smell really bad. Also it's better for the chickens. It's important to seperate the chickens by size because if you have a big chick in with a small one, the bigger ones will usually trample the smaller ones.
Put a hurt chick/pullet/chicken in with grown chickens, move a broodie hen or duck's nest
A hurt chick/pullet will most likely get more hurt if it is put with grown chickens or even with other chicks/pullets. The other chickens could trample or even bump the hurt chicken the wrong way. If you move a broodie he or duck's nest, it might abandon the nest.
Other things you should know Do's and Don'ts:
Put hurt chickens/roosters/chicks/pullets in a seperate container
By doing this, it allows the chicken to heal without disterbence or possible rough houseing. If it is a foot injury, put the chicken in a small container where they can't or can only walk a little bit. You don't want them to hurt their foot further

For chicks that need extra strength, you can buy liquid vitamins. Broodie hens can get off eggs, and hour at a time to go to the bathroom eat, walk around, and drink. If you keep your broodie hen locked up with food and water, and her feet and comb are looking pale, let her out for a while to eat bugs. After she eats a few she should re-gain color. You can let out broodie chickens when their chicks are born and don't have to bother with the chicks getting lost. The hen will take her chicks with her and will watch.