Actually, the only songs i've used arrangements for are Cancer and Piano man. For the others, I watched a tutorial video on youtube or made up most of it by myself. (I could Link the specific videos I used)
Then hey, you've already gotten a start. Even if you couldn't write down what you were playing or identify which aspects of theory you were using, you've still already started to think like you need to.
- Find a Group: I am participating in a 'keyboarding' class in school right now, but all we seem to be doing is learning simple songs out of a level 1 book.
The fact that it's called keyboarding is... concerning. You've tried it and it isn't going well, so I'd suggest moving on and looking for a more advanced group. It's always good to have a group more advanced than you that you can learn from and a group less advanced than you that you can teach.
- Get a good repertoire of classical, blues, and jazz: I for one don't have much of an interest in classical music. I'm not sure why though. Blues... I don't think i've ever tried that before. As for jazz, i've tried to play Rhapsody In Blue but gave up because I am terrible with sheet music.
I hate to be blunt, but I can't think of a better way of saying this... It doesn't matter whether you're interested in these genres. You said your long term goal is to improve your technique, and no matter which genre you're interested in, you can learn so so so much from jazz, classical, and blues. If you can't read sheet music well, you really should work on that. It's hard work, but then, so is being decent on piano in general. Based on the arrangements you linked to, I think starting with Bach's Well-Tempered Clavier would be good for you. Easy to read, just difficult enough to be a challenge for you, and amazing for technique. You don't have to restrict yourself to only playing those pieces, but they will make a great foundation for what you're hoping to do.
- Take a "Dave Grohl" approach to music: My friend does covers of songs and I guess I could attempt to play the their songs but most of them are rock. I guess I could learn to play in my church but i'm too worried about playing in front of people.
Go for it! If you're really truly nervous about playing in front of people and don't plan on ever performing, don't get too worked up about it. But don't hold out on something because of the genre. I mean, right now I'm playing in a rock band, playing polka and Russian folk on accordion (which I couldn't even play until two weeks ago) in a school theatre production, and playing for a production of Vivaldi's Gloria. I hated playing Vivaldi until now, and I still dislike polka and Russian folk, but each experience has been invaluable as far as making good connections and getting plenty of (mostly free) learning.
- Write your own arrangements of songs: As I stated before, I am absolutely terrible with sheet music. For some reason I can only seem to remember middle C on the right hand. If I take a ton of time, I could probably figure out a few measures of a song but it takes way longer than I would hope. Maybe i'm just too impatient.
Again, I hate to be blunt, but you are being too impatient. My first arrangement took months, but I'm a far better musician now because of it. And I never could have written or played any of what I'm playing now if I hadn't just stuck with it.
You need to realise that once you pass the beginner stage, improving takes patience, dedication, and hard work. Playing pop songs is fun, but if you're hoping to grow at all, you have to wander into the not-so-fun stuff, whether that's writing arrangements or playing Etudes or practising the same jazz piece for several months at what feels like a ridiculously slow pace.
Topic: What next?