I grew up with the first animated Teen Titans show and I thought Raven was awesome. Now, I need stories that I can read to learn more about Raven, either solo series/stories or as part of an ensemble that has her as the focus in a significant way
New Teen Titans: Terror of Trigon is a good starting place.
I have mixed feelings about New Teen Titans, but Terror of Trigon is definitely the best arc and Raven’s story in general is the most compelling of the various Titans’ personal arcs. If you can deal with some extremely clunky dialogue in the early years, you might want to read from the beginning.
Though if you do that, note that there are actually two series, each of which changed title. It’s hard to explain coherently, so I made an ugly graphic:
Top bar is the 1980 series listed on DCU as New Teen Titans, bottom bar is the 1984 series listed on DCU as The New Titans. They ran concurrently from August '84 to the Crisis in '86. It’s all written by Marv Wolfman, though, so it’s all kind of connected.