Seeking guidance, portrait retouching techniques

I'm familiar with Lightroom and Photoshop (mostly Lightroom recently), but have little experience retouching portraits. I'm interested in basic workflow and techniques to make portraits "pop." A couple of years ago I sent a portrait that was little more than a snapshot to this forum and a number of people turned it into a masterpiece. Any guidance to start me in the right direction will be appreciated.

My first project is a headshot of my daughter for a business-oriented website. My first attempts are below. I'd also be interested in your opinion on whether these shots are usable, or should I reshoot with better lighting, etc.