Also agree with nailpolishremover advice.
I think you need to find a style you like and try and replicate it. The problem with asking for advice on these boards is everyone has a different sense of style.
I am 42, probably a stone overweight and 5ft 1 tall. I actually think I look pretty good. The advice of mid heel boots, statement necklaces and colourful scarves all scream frump to me I’m afraid.
I think one of the things that can make or break a look is footwear. I tend to wear all white Stan Smith trainers with almost everything, or really chunky Chelsea boots. And despite what people say, still love my Ugg’s!
I would look in H&M for basic T-shirt’s. Less than £10 and unless you are going really high end, I don’t think the quality is any better in more expensive high street shops.
Jeans, I tend to buy from M&S because I can get petite. I’m alternating daily between their Mom jeans and Lily jeans. Mom jeans are baggier so need a fitted top. Also, jeans at the moment, to look more fashionable, should be turned up a little. Really makes a difference.
I liked the second cardi you showed (blue one). Blue Lily jeans, white trainers, white or Breton fitted t shirt and that cardi would look great and not dissimilar to the coat pic you linked to.
Think about what sort of things you do and what sort of outfits you want to wear for each of those things, rather than just buying clothes if that makes sense. And if you are uncomfortable with change, just change one thing at a time and wear it until you feel ok with it, then add something else.