Personally I think anything patterned is out if you want to get this look (well my view of it).
I think key elements are a neutral palette that blends together, a capsule of the best you can afford and getting clothes that fit your proportions.
I would say that translates as very little embellishment, leather/suede bags and shoes in neutral tones but not black unless you are wearing black head to toe.
I think the blazer/shirt/heels/skinnies thing is very cliched magazine editor inspired -chic in it's own way but not expensive looking.
I find discreet accessories look more expensive -not those massive blingy watches that have been everywhere for the last five years. A low key tan leather watch without obvious branding is more fitting. Earrings or bracelet.
With respect to bags I think plain leather with a beautiful chestnut patina or tan suede and no obvious label again works better. I think the design should be in the shaping and not embellishment.
To me a polished palette would be based around navy, tan, taupe,cream,chestnut,charcoal, dove grey,white,camel,caramel, black and mink. Nothing garish and everything understated.
Shoes and bags need to be leather or suede and not too high or clunky.
Pinterest minimalist,neutral wardrobes has some great examples.