I agree with the poster that said to book the most important ones first - even if it's the last day of your trip that you book first. (okay I realized I worded that a little weird - hopefully you all understand!)
WHen I called in January for our July ADR's I got Coral Reef for my first day, then told the CM that I'd be wanting a Le Cellier ADR. She said we should book that one immediately. So we did -even though it's six days into the trip. THEN, I finished booking the others on all the rest of the days. But I made sure to book the Le Cellier earlier in the phone call before everyone else on the other lines snagged up all the ressies!