Just a little bit of confidence to try something different is all you need!
Layering is just that, more than one layer of clothes, eg a shrug cardigan over a t shirt instead of just the t shirt. A dress over a pair of jeans.
As for accessories, just have a look around and see if anything takes your fancy, I started with pretty little junk bracelets, cheap and cheerful and not in your face.
Just get to the shops and start trying things on and looking.
See what other people are wearing when your out and about and try to get ideas that way also.