So... maybe going to write a fanfic... advice needed!

..but I don't watch the anime or anything, and I also haven't played many of the games (my runs consist of Pokémon Conquest which is hardly relevant, Pokémon Mystery Dungeon: Explorers of Sky which is relevant since the protagonists go through a PMD-style transformation and a half-play each of Colosseum, XD, FireRed and Black). Whilst (mostly thanks to Bulbapedia) I have a good idea for the general lore, I don't know much about specific characters and Legendaries' behaviour.

I guess what I'm asking, is that I'm going to write a fanfic which sidesteps these issues and features more or less a different universe where humans aren't even aware of pokémon, and pokémon live on their own isle and are currently fighting amongst themselves (due to Arceus doing the old 'god' thing and wanting to enforce peace by becoming a dictator god) and I wonder if that's really a good idea, especially considering I'm not the best writer around, I just enjoy it...

Help!

To get some ideas watch a few videos of pokemon anime episodes which should give you an idea of what you might be able to use.

Pokemon Mystery Dungeons have some of the best story execution in the franchise. They're good to go off on, especially if the setting contains only Pokemon living by themselves. How to handle the setting of humans without Pokemon is both easier and trickier, though.

Most of all, fanfiction is a literary art for which one expresses his or her creativity, only by coincidence it may be similar to what other people have imagined. If this is something you enjoy, you should let nothing stop you.

The best advise i can give you is, to start and keep at it, don't stop just because nobody is reading. If you're not a good writer then you've come to the right place, because a lot of us here are pretty good (you can try reading some of the good fanfics here, that'll definitely help). Just stick to it if you start, and if you need any help with anything, whether it's writing itself or concepts and ideas for your story, you can stop by the writers block and ask. But most importantly, if you do end up starting, stay committed. If you want to write a great story you have to start just like we all did, at first we weren't good at all, but time after time and with some constructive criticism here and there, we got better.

Good luck :)