If everything works fine simply do the meditation type for 8 concecutive days.
But sometimes the three every day for a week achievments
Grasshopper, Illuminated, Proprietor of Peace
seem to be glitched for some users. Grasshopper tends to unlock earlier than expected while they also may glitch and get unobtainable for your current save file, like the other 2 did for me. Even after doing this for over 2 weeks.
In that case you will need to start a new save file for example on a memory card.
You can manipulate the xbox box time to do this. To do so go offline (drag network cable) set the time back 7 days and do a meditation. The go back to xbox start page and set it to the next day and do the meditation again. Do this till the current day and then go online again to do another one. It is possible that the achievment does not unlock after doing the next one. For me it unlocked after another try around 12 hours later (timezone change to somewhere where it was over 12 hours later).
Back online part is for getting a time stamp on the achievment, if you do not care about that you can do it fully offline.
From what I experienced I can tell the following facts:
1. You can do the same meditation again and again for the 7 days
2. It is not neccessary that you do another one within 24 hours. So you can also do the next one a day and some minutes later which still counts. I guess it counts if you do the next one within the next 48 hours after the last one.
3. Can be done offline with time change trick
4. Does not unlock after 7*24h, but after an additional ~12h
I hope this helps others to clarify some things, as these were a pain in the ass for me as I first tried for almost three weeks, then did the time trick with the current game file, then did it with a new one and then it did not unlock after 7 days but 7 days plus ~12 hours.
If you have similar experiences or know of another way, please comment and I can add it to the guide.