You have brought home your new puppy. She’s a canine tabula rasa — a blank slate ready for you to shape and mold.

To ensure that what gets inscribed is not the behavioral equivalent of graffiti, here’s a trio of common mistakes many new puppy parents make — and how to avoid them.

Crate training. Crates, those portable simulated dens, are everywhere today, and are generally accepted to be a humane, safe way to temporarily contain an unsupervised dog. (Four hours at a stretch is the maximum any puppy or dog should be kept in a crate.)

One goof people make is using a crate that is too large. Ideally, there should be enough room for the pup to comfortably stand, stretch and turn in; a crate that is too roomy will encourage a puppy to eliminate in a far-off corner.

If you want to invest in only one crate, get one that will fit your puppy’s adult size, and then reduce it to accommodate his current size by displacing the extra space with a cardboard box.

Beware of metal crates for small puppies, whose paws can get stuck between the bars; stick with the plastic airline style until he is older. Remember to remove collars. They can catch and strangle a puppy.

Taking food away. A well-trained dog should graciously relinquish something he values — whether a bowl of food or a bone or a toy — to the human reaching for it. But most dogs aren’t born altruists: They need to be shown what is acceptable behavior in human society. And there is a right way and a wrong way to teach it.

Some dogs have no issue with the share-your-crayons concept we all learned in kindergarten.

Some people soon discover that the more they try to take away their puppy’s chow, the more upset he gets. So they try harder, a little indignant to boot: “Hey, I am the human in charge!”

Housebreaking. Consistency is the most important thing in housebreaking.

In the first weeks and even months that your puppy is in her new home, your job is to watch her like a hawk.

But the results are worth it: If your pup is not allowed to roam out of eyeshot, she cannot make an undetected mistake. Every time you allow her to, you establish a pattern and a faulty premise: That it’s OK to pee on the Oriental rug because no one told me otherwise.

Take your puppy outside during the most common “bathroom” times: after eating, waking or playing. When she eliminates outside, reward her, either verbally or with food.