what sizes to use and where

my favorite sizes
First off, if you haven't read about inserts and insert sizing, start here or visit our FAQ page where we break down everything you need to know about inserts.
{This is simply my opinion and no rule is "set in stone", so please remember that these are simply helpful tips to make styling your home a bit easier!}
One of the biggest mistakes you can make when styling pillows is using the wrong size. More often than not, I see spaces styled with sizes that are way too small. Often times one styles with two-three 16x16s or 20x20s, where one 24x24 alone, or styled with a 20x20 would look much more cohesive. 
My favorite sizes to use are 24x24 {you would use a 26x26 down insert}, 20x20 {you would use a 20x20 down insert} and 16x24 {you would use a 16x26 down insert}. I don't love the 16x16 size, and you will see we don't have a ton in stock for that reason.
Another mistake you can make is using one single size in your vignettes. It's important to use varying sizes to create depth and dimension. 
When creating your vignettes, I always suggest sticking to the "rule of threes". Of course, there are exceptions, but this golden rule is the most pleasing to the eye and lends to a cohesive look. 
What do I mean by "rule of threes"? Well, I literally try and create triangles with my pillow vignettes. You create this look by using varying sizes. 
Here's what I recommend
Couch: Flank each side of your couch with a 24x24. if you feel like that may be too large, I suggest a 22x22. Then, pair each 24x24 with a 20x20 or 16x24. I like having three pillows on one side {a 24x24, 20x20 and 16x24} and two on the other {a 24x24 and 20x20}

Sectional: Have a large 24x24 on each end and one in the middle. Sectionals tend to be larger so I encourage you to use 24x24s. I then suggest you pair each 24x24 on the ends with a 20x20 or 16x24. For the middle, I then suggest you have at least 3 pillows. I love a 24x24, 2 20x20s and one 16x24.

Bed: For a king or queen sized bed, I suggest two 24x24s and then one 16x24 resting in front. For a full or twin I love the look of just one large 24x24.

Loveset: One large 24x24 and one 16x24, a 24x24 and a 20x20, a 20x20 and a 16x24 or two 20x20s. The only look I would not suggest would be a single 16x24 {it would look "lost"} or two 16x24s {I never suggest you use two 16x24s alone}.
Accent chair: depending on the size, a single 24x24or 20x20 look fabulous. If your accent chair is larger, add a second pillow to compliment. 
I hope that's helpful my friends! Shoot me an email if there's something else you'd like me to cover!