If you saw my article on the usual, horribly boring, capsule wardrobes, you know I have a bone to pick. Minimal wardrobe can still mean maximal style, and here's how to do it to avoid the dreaded white/grey/black, tshirt/jeans, pop of red, one stripey shirt/dress, capsule.
If you want to stick with white/grey/black you can and you can do it fabulously. If you want to stick with tops and jeans, you can and you can do it fabulously. The more your wardrobe contains neutrals and casuals, the more oomph and interest those items need to have (or have added to them in the rest of the outfit equation).
Personally I go through periods of loving color, and then needing a break from it, but there are still loads of ways you can work with neutrals. White on white prints are even a thing, and it still doesn't feel overwhelming (when you're seeking minimal/modern out of overwhelm) because it's still just white.
Any choices you can make to push it away from being plain- plain t-shirt, plain jeans, plain skirt, plain shoes, will elevate the look immensely. The following are some possibilities to elevate:
Texture
satin
course knits
cashmere
(p)leather
suede
vinyl
velvet
fuax fur
fringe
boucle
tweed
embroidery
embossed
tapestry
popcorn
lace
paisley
leopard
floral
stripes
zebra
fronds
gingham
houndstooth
plaid
polka dots
cabling
Color
color-blocking
two tone
brights
pastels
metallic
monotone
neutrals
Design interest
knots
twists
ruffles
layers
pleating
asymmetry
scalloping
necklines (sharp v, mandarin, funnel, queen anne, cowl, etc)
bell sleeves
sheer panels or other texture
one sleeve
piping