Hello mrwolf
Its practice Practice! I played ffr when i was a kid. I recently started playing again recently. I didn't know my song level so what i did was this;
I went to my unplayed tab and just played every song until i found it really hard, which was for me level 30 to 40 songs.
Then.....
I would go back to my level 20 songs and master them, by getting no Averg, Misses, and boo's. Don't necessarily aim for AAA's just get as close to 0 goods as possible.
Since, i find 50 songs to hard right now. I'm doing ^^^^ once i've shaved off some level 20 songs and got below 20 goods will move to level 30 and 40 ect....
I also try and push myself to do hard songs like for example after doing some 20's will go up to 40 or 50.
Here is a good filter below --- all you do is adjust the song level and set the goods. then, navigate to the song flag " All " and start doing songs and improve your score..The time filter is optional...
As, far as your fingers trying to hit a different letter. The more you play the less it wants to do this hahah. This happens to me too, i will be playing with "as56" and my fingers would want to hit q or 9 like they are my feet lol.