Consider the size of the room that the piece will be going into, and the presence that you want that piece to create. For example, if you have a dining room with large windows, consider getting shorter dining room chairs or benches to not block the view. If you have high ceilings, consider getting taller bookcases to make a statement and draw the eye upwards. Also consider the function of the piece. If you are planning to put component boxes in a TV stand, opt for glass doors instead of wooden ones so you can still use your remotes.