Binning anything from Seasalt would be a good move.
It can seem daunting but check out Kibbe - once I learned my style everything clicked into place.
If you start with the basics - e.g. get yourself some plain t shirts in a style to suit you - I’m a Soft Dramatic - so fabric should be woven and soft not too stiff, neckline v neck but not too pointed, length should never be cropped, t shirt should be tucked in to define waist. This is just an example. Once you’ve worked out your perfect shaped top, look for for tactile fabrics like silk, satin and velvet (in winter) to elevate your tops.
Avoid prints - they are the kids of death to anti frump.
Go for a blazer instead of a cardigan - make sure the shoulders fit you perfectly. Find the perfect blazer and buy it in 3 colours (I have warm cream, olive khaki and blue- grey) which suit you (doing your colours also good - I’m a soft autumn and can discount so many wrong colours now, it’s easy to choose what suits me).
For bottoms find a pair of jeans, palazzo trousers and a mid length wrap skirt that suit you. These will cover so many eventualities paired with your perfect top shape. Jeans wise you can’t go wrong with a bootcut flare or a baggy straight leg (I like mine to have a little distressing to the hem but this is personal taste). You may find the barrel/carrot cuts a little overwhelming - I find they are only suited to the very thin.
For shoes - get a slim style trainer - e.g Puma Speedcats or Adidas Tokyos in a versatile shade - I find off white with a highlight colour less obtrusive than a brilliant white trainer. You will also need two pairs of sandals - one flat and one mid heeled. Strappy, assymetric styles are in this summer. Get yourself a gel pedicure so you don’t have to even think about it. Use gradual tan every other day so you always look a little sun kissed.
This is all totally reversible - you are only 50! Just avoid Seasalt, Next, Fat Face and Boden and you’ll be on the right path. Zara and Mango much better for a browse.