I really want to speedrun something, and I love borderlands. So I saw borderlands 2 doesn't have a ton of runs in my favorite character, zer0. In fact there's only one so I feel confident I could do it! Is there anything I should know or any tips I should use?

You should probably ask this in the game's forum instead, you'd most likely get more answers: https://www.speedrun.com/bl2/forum

In fact there's an interesting topic in there that might be interesting for you: https://www.speedrun.com/bl2/thread/jpzki