I can't give advice specifically for New Vegas(Skyrim modder here), but as far as modding in general, you'll want to start with a mod manager, Nexus Mod manager is my recommendation. I'd highly suggest looking into unofficial patches, which of course fix TONS of bugs, I believe New Vegas has one. Also some tips, I'd suggest using programs such as Wrye Bash, and LOOT to keep your game as stable as possible, you'll want to look videos up of them to learn how to use them, I'd suggest looking to Gopher for videos on modding, he has quite a bit of videos on these. And welcome to modding! :D