I raised them by $1/day. I am at the high end in FCC (just called around in Dec for rates and I was the highest FCC in my city, $10 less than the cheapest center and slightly below standard market rate for centers for my county)
I also charge higher daily rates for PT, and I only accept PT if it fits my available days so I am not giving up a FT space for a PT client.
I have also stopped doing sibling discounts. I charge for 52 weeks/yr.