I try to be a rock for my GF--calm, cool, and collected. Nothing's going to bring me down.
The thing I've worked on the most is to truly listen to my GF. Women aren't looking for us to fix things--which goes against our nature. I don't even have to agree with what she's saying, but I try to validate the feelings behind her words.
I have two daughters and a lot of what I'm doing, as I become a different man, is watch how they respond. They like the more vulnerable Dad. Without criticizing their Mom, I tell them about hopes and dreams that were dashed when my STBXW walked out, just so they can get insight into how wonderful a guy I am.
I also show that I am totally open to suggestions that they make. For example, my youngest (age 19) was talking about the reason she drinks non-dairy milk. So I went out and bought oat milk, the first time ever I just didn't get regular milk. Both girls were really impressed. In the grand scheme of things, it's not that big a deal, but to have let them influence my life, even in a small way, mattered. I also decided that people matter more than ideas or politics. So I get off my high horse a lot when it comes to things like that -- more accepting of the world the way it is, not critical. To my girls, it is a huge thing. I expect it will be the same to a future GF or Mrs Tom.
As for the timing when I begin to date again, thanks for your perspective. I think the right approach is to start slowly, tasting a lot of the wares out there, and make good choices. There's more I could say but probably not here.