Once upon a time, the only person who could see your calendar was you. While working at a local university, I had an administrative assistant in another department get upset that I had blocked my Outlook calendar from the view of others. I guarded my calendar as part of my ongoing efforts to be more productive. I can show you how to do the same so that you can get more done.

A friend showed me his calendar. Two weeks out, he was nearly booked solid. He worked in a company where anyone could request a meeting time on someone’s calendar. As a result, my friend wondered when he would get work done. He won’t until he retains control.
Manage your calendar, or it will manage you.
To begin, I suggest that you use your calendar correctly. David Allen’s “Getting Things Done” systems cautions is about putting too much on our calendar. It says that the only things on your schedule should be actual meetings with a start time and things that need to do on a specific day. Everything else should go on your task list.
You can also include notations about items of importance for that day. That would consist of things like reminders that a coworker will be on vacation.
I’d also suggest that you consider grouping similar administrative tasks that you need to get done. These items, like email, phone calls, and email), into “work time” that you carve out on your calendar the way you would any meeting. For example, you could block off 8-10 am every day (or whatever time works for you) for time to get your work done.
Try not to schedule back-to-back meetings throughout your day. This gives you some breathing room, so if a meeting runs long, it doesn’t force you to play catch up for the rest of your day. Plus, a break between meetings could give you just enough time to return an urgent phone call or to h base with a colleague regarding a followup item.
Protect your calendar so that meeting requests can be prioritized. When invited to a meeting, consider if you really need to be a participant. My rule has also been no agenda/no meeting. If your calendar is online and others can view, no one needs to see the nature of your meetings, only those times that are blocked out. Once you have established the parameters of the work calendar, hold firm. The only individuals who should be able to change your schedule are you or your boss.
If you don’t have an administrative assistant to manage your calendar, consider using an online service like Calendly. Even it’s free version allows people to schedule meetings with you around your available times. Outlook does the same thing, but Calendly will enable you to have greater control.
Because so many of these issues are due to online access, you might be tempted to return to a paper calendar. Many people do. Just remember that in order for it to be effective, you need to carry your calendar with you at all times.