I'm regularly trying new calendar hacks in an attempt to gain control and freedom over my days. (Here are some of my top calendar hacks.) My newest trick is to defrag my calendar into working groups. The idea to defrag my calendar came from Lara Hogan. Her post on Manager Energy Drain is a great read and even includes a worksheet to help with the defrag.
The concept is pretty simple. Group your meetings into three types based on the type of energy you use for each event: listening, strategy, planning. It also helps to color code your meetings based on these types of mental energy. Once you've done the groupings, then move things around to avoid too much context switching throughout the day.
I also added in working blocks at the start and at the end of my day. Each day and each week is like a yoga class, because there is a warm up and a cool down phase to each day and to the week. For example, if I can avoid it, I don't jump right into strategy brain on Monday morning. I like to use my planning brain later in the week, as it lets me review the week and plan for the next week. My empathy/listening brain is best earlier in the week.
These are all suggestions and guides. Of course, there are exceptions and one-off's. This is about practice, being conscious, and being deliberate about how I spend my time and energe. That's never a bad thing in my book.