The wiki links are just for starters. There's plenty more information about both of these groups out in the world (though granted, like any historical subject, there are still many unanswered questions).
I’m not a strict monotheist, but If I were and didn’t identify with any existent monotheistic religion, I would make offerings of libations and incense to God at a specific spot every day and ask him every morning and every night how he wants to be worshiped. At night, I would meditate on his qualities and attributes before falling asleep. Prayers of thanksgiving and supplication would be said at every offering and before falling asleep. This is just what I would do. Perhaps God might speak and reveal something about a ritual calendar, proper offerings, righteousness, a great plan, etc.?