This is a really interesting thread. A super minimal, easy to mix and match wardrobe has been my goal for years. And while I've cut down to half my original numbers for my 4 season wardrobe, I still have 4 very varied seasons and I seem to prefer a little more variety IRL than in my head.
I've simplified and complicated my wardrobe over the years by:
-I run on team cold so for my warm weather clothes my items need to layer. This has helped me stay away from open knit sweaters or tops with sleeves that do not layer well with a blazer or cardigan (such as a bell sleeve) over it.
-I've limited my 3/4 sleeve tops to 3 and none of my blazers have 3/4 sleeves. I used to purchase lots of 3/4 sleeve items but found layering them in non summer months a real challenge. Now I have a couple for variety but since it's only 3 if they sit for colder months it's not a huge pile of clothes sitting unworn for a large chunk of time. Also because it's a small number there is a high chance by the end of the season the item is ready for purging anyway.
-I do not own any skirts and I own 3 dresses. All 3 dresses are occasion specific (business or special occasion). I've never found pairing skirts with tops easy so I stopped trying. And I noticed I'd rather grab a pair of shorts than a dress in the heat so I phased out a large skirt/dress wardrobe that mostly sat unworn and that really cut down my wardrobe size.
-I own very few season specific items. I do like to dress for the seasons but I am more interested in versatile items. So I limit my seasonal clothing. For warm months I only have 2 pairs of shorts, 1 pair of white jeans, and no bottoms that are cropped. I wear jeans to work year round so it's easier for me to have jeans that are full length and not cropped. For toppers I only have one (a cardigan) with 3/4 sleeves. All the rest are long sleeves and colors I can wear year round. I just push up the sleeves if I want to expose some forearm. When I purchase toppers I try to pick neutrals/seasonless colors that I can wear year round.
-I add a seasonal vibe with my layering pieces. Right now in the heat, that means short sleeve tops in prints of the season. But all the prints can be paired with my toppers. Since my layering items are washed frequently they tend to wear quickly and be replaced seasonally. This freshens up my wardrobe and keeps me from having layering orphans.
-I am very selective with my toppers. These items are usually pricier, and worn year round (I'll wear a blazer in chilly a/c at work) so neutrals work better here. But I do have color with these so maybe it's the materials I am paying close attention to. I can sport a tan blazer year round even though you usually see them in spring as long as it is not linen which would make it too seasonal for my year round needs. I will purchase a seasonal item (such as the plum Tory Burch sweatercoat from NAS) but I'll wear that item for fall, winter and spring and just vary up the layering items and bottoms to make it work (plum is lovely with white in spring and a sweatercoat works great on rainy cold spring days and the plum will also be lovely with black for fall and winter).
-I stick to one heel height for my bottoms. All my bootcut jeans and trousers work with a small heel. If I want to wear a large heel I'll wear skinny jeans or a dress. When I first found out about PPL I went nuts with varying hemlengths on my jeans. But it was too confusing! Now when I shop I know the heel height I need and I just look at footwear that has that heel height. This has really simplified my shoe shopping.