How do I know the correct size of a chandelier for a dining table?
A general guideline is to choose a chandelier that has a diameter equal to one-half the width of the table. The general appearance of the chandelier must be taken into account, too; that is, if it is a light airy piece it may be slightly larger than the standard.

How low should a chandelier be hung over a dining table?
Generally there should be 30" between the bottom of the chandelier and the top of the table in a room with an 8' ceiling. If the ceiling is higher, the distance between the bottom of the fixture and the table should increase slightly. Remember that the chandelier should provide light for the table, but not be so low as to block anyone's line of vision when they are sitting at the table.

What guidelines should I follow in choosing a chandelier for a foyer or other room?
Add the room dimensions together. If the room is 14' by 16', add 14 + 16. The answer is 30, which means that your chandelier should be approximately 30" in diameter. Again, remember that other factors such as the height of the ceiling may influence the proper size.