Q: Best way to send files back and forth between PC and Mini

I know something similar like this has been asked a million times, but I couldn't quite find the answer I need. Basically I work on the PC and my new Mac Mini, and I want to be able to quickly share files between both of them. I know I could use a USB stick, but seeing both machines are sharing the same internet connection on the same router I was thinking there's a way to do it with that or wirelessly? migration assistant seems to just be about sending files to the mac and that's it.

Thanks for any advice.