If your coffee table has a lower shelf you don’t have to fill both levels but if you choose to try lining up the items on each tier. Use two pairs instead of threes and don’t forget to play with heights. A lidded storage box or small basket can help keep the bottom level looking sharp while giving you a place to stash items like remote controls.
For a perfectly square table you may be tempted to use four matching pieces for a perfectly symmetrical look. However you can get a more intriguing look by using two pieces or groups one in each corner. Try a tall vase or lantern in one corner with a stack of two or three books in the other (and an airy sculptural accent on top).