Gosh, yes it is really hard!
Fatface/boden/joules/mistral/whitestuff/seasalt are all a bit boring now and just not modern or fashion or fun or even flattering. It is all weekend-dressing if you don't mind looking like a playgroup teacher (or is that just me)
Hush used to be a bit more fun and fashion, but ALL their dresses are baggy and wide and short on me (the cut has gone weird, and some is now polyester 
Toast used to be great, but is now all 100% Soviet librarian. As is Cos.
Uniqlo sometimes ok, but their sizing varies wildly, I can be an M or an XL there (size 14)
Whistles/Hobbs/LKBennet/Reiss are too formal for me
I started browsing in boutiques, and noting down brands I like, the scouring ebay for these lesser known brands.
Even if tortured I would not tell you which they are 
H&M sometimes do nice stuff (google dresses and start with the most expensive)
It is hard work, dressing nice.
There are too many days I just wear my fatface clobber..... I give up 