Choosing a right dog for a pet is very difficult, difficult because there are so many things to consider.
First, You must know what size of a dog do you like,
Large? Medium, or toy?
In choosing a dog, its really important to consider the right size for you. you might get a big dog but you live in a ver small house or you might get a small dog but you live inside the Hacienda or ranch! heheeh you might lost your dog!
Big dogs really needs a large place to move around and cool place. Small dogs tend to be delicate and vulnerable. Being stepped on or mishandled can cause serious injury. Small dogs also are sensitive in cold temperatures, be ready to help them warm.
Secondly, you must know the purpose of the dog for you?
Working Dog? Cuddle Dog? or just a dog that walks a lot at home. Most of the Big dogs are working dogs, working dogs are pets that can be trained to assist masters or entertain.
Cuddle dogs are usually the toy dogs. Shitzu, pinscher Chihuahua and many more.
Third, where do you wish to place the dog? Is it inside? outside the house? or both.
If you are undecided what size id appropriate for you and you really want to own a dog, better get the medium sized dog its less high maintenance and low cost on dog food. By the way, mine is Beagle. hehehehe