So I'm in the Ebonheart Pact, and after completing the main questline, I get sent to the Daggerfall Covenant. How do I get to the Aldmeri Dominion? Do I have to complete all the Daggerfall Covenant quests first?
You have to complete the main quests in the DC area. When you press J and go to Cadwell's almanach you can see where you have to do quests in order to complete the area.
You have to work through the cadwells silver quests, about 4-5 per covenant zone. You can keep track of your progress by looking in your journal and checking the cadwells almanac tab.