[reuben_tate]

Like what igr said, just poke around and see what you can do. Don't just poke around the 66's either, go explore the range a little bit; chances are you'll find some files that are "supposedly" harder than the rest that are actually easier for you, I know some people that can AAA things that I can't even FC yet and on other songs, I can sdg and they wouldn't be even able to ddg, everyone has different skill sets.

Also, another bit of advice, try playing hard files (high-fmo's/low-fgo's) that are like a beef-ed up version of the song you are trying to get oni on, that way, when you go to the oni-get file, it'll feel a lot easier :P