This is one of the initial questions which you have to answer.

How much space will the bird need?

Larger birds and even some of the small ones are very active physically and need big cages and space in which to play.

Is there any free time for the bird?

Probably this is the most important question. Birds are intelligent,

1.    Good hygiene – regularly clean the bird cage and the appliances in it. The cleaning must be accomplished minimum twice a week . 
2.    We mustn't let our birds have contacts with wild or free – living birds, who are the main carriers of diseases and infections . 
3.    Do not put the bird cage exposed to draughts – the birds can catch a cold ,

The African Grey Parrot scientifically known as Psittacus erithacus. Here are two types of African Greys - the larger Congo (has bright red tail feathers) and smaller Timneh (darker tail feathers). No one really knows when the Grey African Parrot was first found but it said that King Henry VIII had an African grey parrot as a pet. The African Grey Parrot is a large bird that can grow to 12 to 14 inches in length. The Timneh subspecies is a little smaller. Their tails are quite short and they don't have very beautiful colored plumage. But all this is compensated by their intelligence.

Coming home to the enthusiastic greetings of your flock after a long day at work is one of life’s greatest pleasures. Before you add companion birds to your family, though, check these tips and make sure you’re prepared for the leap.
Songbirds and pigeons are intelligent, social animals. (Okay, some people might quibble about the intelligence of some rock pigeons…) The same cleverness and flocking instincts that make them particularly attractive pets are also reflected in some of the difficulties in keeping them healthy.

What is aspergillosis and what causes it?
Aspergillosis is a respiratory disease of birds caused by the fungus Aspergillus, which is found almost everywhere in the environment. Aspergillosis fumigatus is the most common species of the fungus to cause disease, although Aspergillus flavus, Aspergillus niger, and others can also cause problems. Aspergillus grows readily in warm and moist environments. The microscopic spores of the fungus become airborne, and poor ventilation, poor sanitation, dusty conditions, and close confinement increase the chance of the spores will be inhaled.
Usually, the fungus does not cause disease, however, if a bird does not have a healthy immune system, it can cause illness. Predisposing factors include other illnesses, stress, poor nutrition, poor husbandry or unsanitary conditions, another injury to the respiratory system (e.g.; smoke inhalation), and prolonged use of certain medications such as antibiotics or corticosteroids. The combination of the number of spores in the environment and the presence of predisposing factors determine which birds are most at risk of disease. Aspergillosis appears to be more common in parrots and mynahs than other pet birds.

Just like children and pets like cats and dogs, parrots and other pet birds sometimes exhibit behavior problems that their caretakers find difficult to deal with. While there are a number of ways that birds can misbehave and irritate the people that they live with, there tend to be a few behavior issues that are more widely reported than others. Thankfully, most of these problems have rather simple solutions if owners put forth a little time and effort. 

Bird Grooming and Cleaning
There’s no getting around it, birds are messy. Given a chance and the proper tools, they keep themselves clean and well-groomed, but you’ll need to clean their cage.
Birds spend an average of a third of their waking time preening and grooming them own. If they are flocking birds, as most pet birds are, they might groom each other, too. As long as they are not actively pulling out their feathers (a potentially-dangerous condition known as ‘French molt’), this self-grooming is a good thing. The down and contour feathers are essential defenses against the weather and other hazards, and the flight feathers need to be in good shape for efficient flying. For most water birds, grooming also allows the animal to water-proof its coat so it can both keep warm in the water and avoid uncontrolled sinking.
Keeping the bird’s home clean is your responsibility, however. This is a constant effort, as the cage should be cleaned every day and the surrounding area will need to be tended frequently. However, it doesn’t need to be difficult. A little preventative maintenance can work wonders.

Bird Food & Nutrition:
When it comes to food, your pet needs a balanced diet as well as lots of clean water to stay in tip top shape. Feeding your bird correctly for maximum health has never been easier than it is now. For a long time, the standard way to feed pet birds was to buy a seed mix, and possibly supplement the seeds with some fresh greens and a piece of fruit. Most kinds of pet birds see seed mixes as tasty, but the mixes are fattening and lack many essential nutrients. As a result, many pets died young from preventable diseases.
In the past couple decades, research into avian nutrition has made huge strides. This research has resulted in excellent pellet foods and ready-to-serve mixes for many species of bird, which will help ensure a long healthy life for your pet.

Birds Need Fresh, Clean Water:
All types of birds need to have fresh, clean water available all the time. In the wild, some flocks of doves travel for more than sixty miles every morning and every night to get to water. The trick is keeping the water fresh and clean. Your bird will get food, and feathers, and possibly droppings in his water dish, even if you use a hopper instead of an open bowl. Clean the dish and replace the water twice a day.

Bird Training and Hand Rearing

From stepping up to learning to talk, taking the time to train your pet bird can be a rewarding experience for you and your feathered friend.
Birds are more intelligent than most people give them credit for. The insult “bird-brain” doesn’t really suit the majority of pet birds. Like most intelligent animals (including us), pet birds become bored and restless if they don’t have something to occupy their minds. Also, there are certain behaviors that will make it easier for your pet bird to fit into your family. Chew toys and ladders are a good and necessary start, but you should consider training your bird.

Good toys have different shapes and textures for the bird to explore and destroy.  At least three toys should make a bird work for food    Working toys are toys that make them work for their treats or favored foods. Parrots in the wild will spend the majority of their waking hours, hunting and foraging. Toys stimulate their mind and help replicate actions

The nesting season is an important time for birds. Its springtime and birds must now turn to nesting. They turn their full attention and energy to nesting during springtime. It is a stressful experience for a bird to move to a new location.They need to adjust to new sights, sounds and foods.