So obviously there arn't any out yet as the game was just release, but as people start to develop mods, where should I go looking for them? I'm a first time PC player, so I don't have much experience...
One really simple one I hope someone puts together soon is the ability to walk/run forward while having the 3rd person camera free to move in a full 360 around your character, ala Fallout 3/NV/H1Z1. I didn't realize I looked at my character while he/she moved so much until I lost the ability to do so...

http://www.nexusmods.com/fallout4

And yes, there are several mods out already.

And modding can be a bit daunting for a beginner, check out these https://www.youtube.com/watch?v=xVfr9pWO6xE&index=1&list=PLE7DlYarj-DdGbu7-Chui4ZQuZZCGbpWl from Gopher for a very clear explanation.

But stick with it, because the rewards for becoming a competent mod user are astoundingly great.