Artifact Power can be found in chests that are in the wild similar to Draenor Treasures, you can also find useless goodies there too. Order Resources can also be in these chests once you get friendly with each faction (must also be L110) you can unlock world quests which give you a bunch of order resources and AP (daily/weekly reset?).

At level 110 you also get more AP in random dungeons per boss so it becomes a grind.