Advice or success stories for timid dogs

I recently (this past Sunday) adopted a very shy dog from my local shelter. She is 8-9 months old and I believe she is a black mouth cur shepherd mix. She’s curious and starting to engage. She follows me, rests nearby, and plays with toys and my other two dogs, but she’s not ready to be touched yet. Progress is slow and non-linear. Some days she has threshold fear and it takes her a long time to come inside from being in the yard, other times she comes straight in. Sometimes she follows me around the house, other times she darts away when I look at her or turn my body toward her. I’ve read a lot about timid dogs and I’m trying to follow the advice about basically ignoring her and just letting her exist.

I’d love to hear tips, encouragement, or success stories from anyone who’s helped a cautious dog feel safe, confident, and hopefully eventually comfortable with touch.