I've been looking into reaching out to Fortuna, but I don't know where to start (since I keep picking deities that aren't commonly worshipped). Do you happen to have any resources you can recommend?
Reference wise, those two should get you started:
Fortuna: Deity and Concept in Archaic and Republican Italy by Daniele Miano
The Goddess Fortuna in Imperial Rome: Cult, Art, Text by Darius Andre Arya
The framework you choose as to how to approach her is ultimately up to you (that is: syncretic greco-roman, republican roman, imperial roman etc..). This is something you might choose while reseaching her as well. The more knowledge you’ll have, the easier it’ll be to actually know what and how you want to do things.
If you choose to go for a more roman approach, please refer to @amor-augusti. He also has a masterpost of good references on roman religion. Maybe he has something about Fortuna too, I haven’t checked.