Making non-alcoholic glögg is super easy. Get your favorite fruit juice, add some whole spices, and heat it to just below boiling for an hour or so to let the spice flavors blend with the juice. It also smells good during this time, so don't rush, enjoy the process.
Good juices to use:
blends of any of those
anything else you can imagine (for example, I saw some rhubarb juice in a German grocery store, that could make an awesome spiced drink too)
Good spices to use:
black peppercorn (trust me on this one - so good!)
Sweeten with sugar or honey, if desired.