There are certain factors which need to be kept in mind while selecting a puppy. Then can basically be distributed into two categories, namely size and ***.

The categories are discussed below, In Detail About Dog size and ***:-
Size: A big sized dog needs regular exercise and you must happily take him out at least twice a day for long walks. On the other hand, if you can't afford this, selecting a smaller dog is a smarter decision. He will not need as much exercise and so will be more suitable for indoor life and small homes. A big dog requires more space. Never dream of keeping a Great Dane in a two room apartment on the sixth floor. The shorter the space you have, the smaller the size of the dog you should settle for. The less energy you have to take care, the smaller the size. Another consideration is the feed. A bigger dog needs more food and is relatively expensive compared to a smaller one. A big dog is kept as a guard dog, a deterrent to thieves and burglars. Though a smaller one with a sharp bark can more or less serve the purpose.

Keep all these factors in mind while selecting the size so as to suit your individual requirements.
*** :- This is a rudimentary and crucial decision - whether to select a dog or a bitch. Don't go by the stories contending the superiority of a male or a female. They have no scientific basis. The animal's individual disposition varies irrespective of the ***. Generally, females have a sweeter disposition. Females come on heat when they are ready to be mated, once they are between six months to one year of age, while males do not experience any such change.