Accessorizing in Threes

I love my McCoy pottery collection (better photos with my many new additions coming soon) because it is so easy to display it: I just collect it all into a nice, glass front curio that's part of our entertainment unit.  Oh, don't get me wrong, I fuss with the arrangement and group by colour.  But, for the most part, it is easy-peasy because I just stick 'em all together.  

Accessorizing gets trickier when I start combining disparate pieces because I like to think about scale, colour, and balance.  Plus, I hate when an arrangement looks too matchy-matchy or too flea market messy.  To help, one of my tricks is to group objects in threes.  With this trick in mind, one of our side tables beside the sofa looked a little bare, but I was waiting for the right piece (I hate settling).  With my Mom, my thrifting lucky charm, at my side I found a pretty, paisley-shaped vintage dish - likely a planter - that picks up on the turquoise of my large McCoy planter and the warm, coppery hue of the vintage teak side table.  A small addition, but it really makes the arrangement "click" and adds some new texture to the space:

With just the McCoy planter and vintage Lotte lamp:
 

With my new thrifty find, a vintage dish with interesting colour and texture:

And yes, I'm kind of obsessed with it.  I'm not a person who always comes home with something new.  I try to spend carefully and buy things I will love for the long haul.  So when something meets the "come live in the townhouse" criteria, I get a little giddy.  Am I alone in this?  Hope not, because I snapped more photos!

You know I don't believe in "rules" (put as many object d'art as makes you happy) but here are a few examples where the three item trick was employed by pros:

Laura Casey Interiors; DIY Network; Sarah Richardson; Sarah Richardson

What is your tip for making a small, but notable, change?