As many wise people use to say: it’s not a matter of time is a matter of priority.
You’ll be always overwhelmed by something (that someone states it’s ) urgent and important. And you have to decide who drives in your life: you or the others.
When you plan your day / week / life / meeting / … put your important stuff first and let other activities go around these kind of milestones. They are your handles, plan everything else and act as if they cannot be moved. Subordinate every other decision to preserving the important stuff.
Another key to an effective Time Management?? Delegation!