Here are some examples of how to choose objects that are similar. Same vases, each with 1 same flower, but each flower a different color 2. Same candles, but a different height or width 3. Odd number of objects look best when using similar objects in a cluster or in a row. Even number of objects look best when making a grid formation.
Cluster formation is great for candles or small photo frames on a table.
You need to have different heights in your objects to make a cluster. The largest in the back, medium to the right front and the smallest to the left front of the largest. Row formation is simply objects placed in a line like on your mantle. Grid formation is good for medium to small pictures. Process for Arranging Objects Simple Arrangements Using 1 or 2 of the principles for arranging objects is good for small spaces, window sills, small tables, or center pieces.