To be able to determine exactly what your decoration will look like, actually set a table or set up the decoration in a room and see what the total appearance is well before the wedding. Sometimes what seems to work well together in theory is not as elegant when actually presented, so this test run will allow you to make any necessary last minute adjustments to the decorations.
Wedding decoration plans should be one of the things that you consider closely. There are many great ways to decorate and you will want to give yourself enough time to find all of them. Most importantly, you will want to create the mood that works well for your wedding specifically.