Cosmo Run

As the achievement says, you need to complete one run every day for 7 days in a row. Since you have to do quite a bit of grinding anyway, you can definitely get this done naturally. If you don't want to have to worry about this though, you can simply change the date on your device, play a single run, change the date forward a day, and repeat until you do a run every day of a week. The achievement will unlock after the 7th day.