It can be so variable I think it's difficult to pinpoint one day in particular which is busier than the rest, however I do keep records of how many I see and over the past 3 months and have worked out an average for each day. I have found the following from most to least bookings;
Thursday
Wednesday
Friday
Monday
Tuesday
Sunday
Saturday
But this is going to vary for everyone and what's good one week isn't the next! For instance even though "on average" Saturdays are the worst day for me last Sat I had 5 appointments, 4 of which were hours which I consider to be a good day - in fact my best all week!