I will get around to writing guides myself one of these days. Until then, here are things that other people have written:
- Yin's Oto Tutorial - This is the guide I used. It's extremely thorough, which will either be really good or really bad depending on how well you absorb copious amounts of new information.
These are other guides that I haven't looked at extensively, but might be useful:
- Iroiro - Has all sorts of useful features (lyric conversion, batch lyric replacement, and so on)
- Resampler patcher - Significantly speeds up the rendering process
- Clipboard (clipboard.zip and pastespecial.zip) - Allows you to copy and paste tuning/formatting/lyrics/basically anything between notes