Overhead Lighting
Most bedrooms have some type of overhead light. Sometimes they're fixed flush to the ceilings and sometimes they hang down. A hanging fixture, particularly a chandelier can be quite lovely in a bedroom. They provide a beautiful decorative element along with a general glow. That said, it's important to note that a single overhead light is not enough.
Table Lamps
Table lamps are important for providing task lighting, and in a bedroom that usually means there should be one on either side of the bed (or one side if it's a twin bed). Just make sure that the light shines downward so that you get enough light to read by (or perform whatever task it is you need the light for). For a formal and symmetrical look place a matching pair on the bedside tables. If you prefer a more casual look it's perfectly acceptable to use lamps that don't match.
Depending on the size of your room you might want to place another lamp somewhere else – on a chest of drawers for example. Wherever you need a bit of extra light feel free to add a lamp, because an overhead fixture often isn't enough.
The size of the lamps you choose will always depend on the size of the bed and the bedside tables. A small table will require a small lamp while a bigger table will require a bigger lamp.
Sconces
If space is at a minimum, sconces can be an excellent alternative to table lamps. Install them on either side of the bed – high enough that you don't hit your head, but low enough to get the benefit of the light. Again, make sure the light shines down to illuminate the necessary area.
Floor Lamps
Floor lamps are great for adding light where there's no table surface (they're often used in corners). They don't take up very much space and are great for distributing light in awkward spaces. In a bedroom this could be next to a reading chair.
Bedroom Lighting Tips
Try to avoid using track lights or pot lights in a bedroom. The bedroom is the one room where you want a soft, romantic glow. Pot and track lights tend to look a bit too industrial.
Mix task and ambient lighting by using a few different types of lighting (table lamps and sconces, sconces and a fixture, etc.)
Add a dimmer switch to every light in the room. Dimming lights creates instant ambiance and creates a much more flattering glow.
Be sure to include enough light in reading and other task areas.