I noticed throughout your post you said "turns out she didn't like me" twice, as if this was a simple boolean value that you have to find out the value of.

The truth is that attraction is pretty malleable and it's totally possible that your friend had romantic interest in you which disappeared while having dinner with her, or that the potential date that cancelled on you twice was turned off through non-physical interactions (texts, phonecalls).

Your 3 step action plan sounds solid though. The fundamentals of pick up artistry will also help a ton.