Accuracy is based off your top scores, so when you farm for pp, high acc FCs are what will get up there the easiest. 98.53 is actually pretty bad, and it's only that low because my 2 top scores are overweighted DT farm maps that I choked on lole.
The highest star rating I have passed is 7.6 I think, but I usually play ~6 stars.>what are some tips to play better
Play more. That's pretty much it. What's your playcount right now?
I found that playing maps that are slightly above my skill level and trying to pass them helped me improve more than farming FCs for ranks.