Ideally, parakeets should be able to have at least one bird-safe room in your home where they can fly around. But even so, a large metal parakeet cage is essential. Get the largest parakeet cage possible, as the birds will think of it as their house. When inside they will want to move around, climb up and down, play, even fly a little.
Covering the cage at night gives the birds privacy and prevents drafts. Not all birds like to be covered - if you find yours do, you can make a beautiful cage cover that says something about your birds and how you feel about them.
Bird cage covers should be natural cloth with a tight weave, not flannel or anything that birds can get their talons caught in. The material should be medium weight -- calico or denim are fine choices. If the cage is bell-shaped, an old denim skirt or a cotton petticoat make beautiful covers. If you don't have any long enough, measure the cage top to bottom and around, then check your local thrift shop. If you want to make the cage cover by hand, use a pattern for a peasant skirt.
If the cage is rectangular, try this easy style. Measure the cage's height, top, and all four sides. When you buy the material, remember to allow for seams and hems plus some slight overlap. Lay it out and carefully cut out the sections for each side and for the top. Pin the pieces together and try it on the cage. If it hangs all right and completely covers the cage, it's fine.
Hem each edge of each of the side pieces. Optionally, sew a contrasting fabric or ruffle at the bottom of each side piece, but don't use lace. If you are going to embroider the side pieces, this is where you do it. Don't use sequins, just regular cotton floss. Embroider colorful flowers, leaves, feathers, trees, clouds, the birds' names, anything that comes to mind.
Sew the side sections to the top section but not to each other. Now try it on again; make sure everything fits well and looks nice.
You don't have to sew the sides to each other. In fact, it is often better if you don't, but just let them hang down so that they overlap slightly. This way, you can use the cover to let the birds know it will soon be time to go to bed. About an hour before their actual bedtime, put the cover over the cage with just two sections down and the other two folded back. You can check on the birds to see if they're okay by gently lifting one side section part way -- you won't have to remove the whole cover.
However, you should also sew Velcro strips to the edges of the sides so that the cover can be closed around the cage. This is essential if you take the birds to the vet in their big cage rather than putting them in a small travel cage. For the round cage, put the skirt on and tie a sash or belt securely around the bottom. When you travel with birds they should always be completely covered and the cage secure -- put a twist tie around the latch, or even a small lock.
When you cover the cage and tell your friends good night, also shut off lights and noise in their birds' room. Some birds like CDs of environmental sounds on low volume for an hour or so.
You should have at least two parakeets. They need each other's company. If you have more than two birds, get two cages. It is not true that if you have more than one bird, they won't learn to talk. Birds are very intelligent, and learn by repetition. They may speak bird language to each other, but with lots of attention and personal interaction, you can teach them to speak your language, too.