Here is a basic checklist of environmental hazards:
Puppies can open loose cupboard doors. Buy cupboard door protectors or get out the good old duct tape and make sure that the cupboards that are low either can not be broken into or do not contain hazardous elements!
Puppies can chew light cords. Arrange your home so that light cords, TV cables, computer cords, and so on, are hidden behind heavy immovable furniture or are enclosed behind barriers.
Large Breed puppies can put their front feet onto ALL the counters. Push back items that they can get into, take them off the counters, or be prepared to have your most valuable items (such as your TV remote control) dragged off and chewed!
Clothing articles can be DEADLY. I personally have known several puppies around the age of five to six months that have died from ingesting socks or chewing on scatter rugs.... fabric often balls up and creates an intestinal blockage. By the time the vet discovers it, it is too late. Don't allow your puppy to drag around socks or old towels, take them away and substitute with a dog toy.
Common houseplants can be poisonous. Make sure you know which ones are, and keep them out of the environment where your puppy will be. You can find the poisonous ones through a quick check on the internet.
Household poisons used for insect or rodent control should be absolutely out of the question in the puppies' environment. Simply do not apply poisons in areas that your puppy has access to, under any circumstance!
Toys should be dog toys. Left over trucks from the kids' toy box are NOT GOOD. Items which have small parts which can be chewed off or swallowed are NOT GOOD. Likewise, most bones are NOT GOOD. Vets will tell you of the numbers of surgeries they have performed to remove bone shards from the intestines of dogs. If you must provide bones, the bigger "knucklebone" is a good choice because it will not shred off into sharp shards.
Sticks are the favorite as far as retrieving, but sticks in the mouth of running puppies are dangerous. They can jam that stick into their throat if they run into an immovable object, OR they can take out the eye of another dog or even a child. Use good dog toys for retrieving...and be sure the toys are not too small for the dog's mouth and can not be swallowed!
Nothing "settles down" a hyperactive puppy like a good exercise session. Do not over do, and be careful that you do not demand too much of your puppy before its young bones are ready....but go on walks, by all means. And make these walks a time to teach your puppy the basics of polite manners...sitting when you come to street corners, not barking at strangers that you meet. So that means these walks must be ON LEASH. (It's better exercise for you, that way, too!) After the "controlled" walk, a good run in a dog park, off leash, or a good swim in a nearby pond are excellent ways to burn off excess energy. The rule of thumb for walking distance for a pup is "no longer than 20 minutes" before six months of age.
Nothing is as important in the care of a puppy as regular vet checks. Be sure that your puppy is immunized at the right times, fed well, exercised well, and spends the majority of its time in a "puppy-safe" environment....and have fun bringing up your puppy!