There is a real difference between being lonely and being alone.
Being lonely is suffering through an emotion. A feeling of emptiness that lives inside you that comes from your perception of being isolated or separated that can be just as intense when you are a million miles away from civilization as it is when you stand surrounded by millions of people.
Being alone is just simply not being near other people. No feeling of loneliness is necessary. You just occupy space absent of other people.
As a precaution to your personal sanity, it takes a little periodic alone time. Time completely to yourself to allow yourself the chance to reflect on what components of your life are currently working for you, and what components are not.
Just as you might look at a messy room from the doorway to see how much work it may take to clean it up, backing away and taking a break from the people and processes that clutter up your everyday life can allow you to see if their presence is necessary, or possibly harmful.
Planning time alone is as simple as planning for time alone. Schedule regular periods for personal reflection and review. These periods of hopefully quiet solitude should allow you to tune out the entire world and all the people in it.
The key to this is quiet reflection. This must be done in a quiet place with very few distractions. Preferably a place without a phone, television, or internet access temping you into doing anything other than thinking about yourself and your life.
Make some intentional alone time to take a tough look at yourself and your life. After some reflection, write a plan of action as to how you will work to de-clutter and de-fuse your personal complications. Then go out and do it!