Getting max style was a huge pain. I didn't even realize there was a style rating at first.
I used this as a guide:
http://i.imgur.com/qcRZPpJ.jpg
I'm not sure if you can max style in a day... it took me 3 days, especially since some activities can only be done once a day. I used the Stone Emporium guy as a benchmark for how close I was... he eventually lowers the price on mega evolution stones to 10000 if you've maxed style.
Also, the O-power guy shows up in Cafe Introversion... took me a few tries to look up the real answer.