Sure -- this is a screenshot of what my calendar looked like earlier this morning. The all day section (at the top) has a couple of "must do today" tasks. For example, the data collection computer has to be moved today because we're starting a new study on Monday, and it got put on the must do today list instead of the task list because the new space wasn't available prior to today.
The two things that are color coded are the tasks that, all things being equal, I'd most like to get done today. I've found the pre-identification of 2-3 tasks overall and 2-3 writing tasks to work well for me (I label the general tasks MIT for "most important tasks" -- I think I picked that up from a blog post somewhere, although I can't remember where).
I actually pre-identify at the end of the work day the day before, because I've found the ability to "hit the ground running" in the morning to be very beneficial. The color coding makes it very clear that the MITs and the writing tasks aren't "MUST DOS". I should also mention that these are just notes of things that are on my tasks list -- the tasks list is the full capture of what needs to get done; the MIT/writing tag on the calendar is just a convenient way of reminding me about the decision I've made about which ones to focus on.
I've found that the real key to my system not getting muddled up is to make sure the distinctions are clear between: must do at a given time (the stuff that is in the timed section of the calendar), must do today (all day events), and would be nice to do, maybe today (other tasks, including but not limited to the MIT and writing list). The MIT/Writing identification on the calendar only works because it is crystal clear that those are different than must be done things and because, if they're not done at the end of the day, I don't lose any sleep over it -- they're on the tasks list and they'll stay captured there until complete.
I hope that helps -- if not, let me know and I can try to explain further.