So! I just got Stardew Valley a week ago, and I'm absolutely in love; been nolifing it sorta (38 hours on record, Steam says). Thing is, I'm absolutely clueless when it comes to actually modding it; making the mods rather than installing them, I mean. Basically, one of the things I want to do is mod the accessory I'm using (the red collar/choker/necklace thing) into a choker like the one I did up for my portrait. Once I know I know the basics of it, I'd be happy to make accessory mods for people!
Here you have an basic modding guide by Alpha_Omegasis: https://docs.google.com/document/d/1s5cEf7NLvJ6iIu6kh1oRGKE-Uw25Aak0xs2S5_MA9to/edit He explains it pretty good. I hope that helps If you have any questions, feel free to ask!