Disneyland opens at 8am most days, you should be at the gate at least 30 minutes prior to open- if not an hour early on busier days of the year. This will allow you to be at the parks for 'rope drop' where you can be first in line at the 'ropes' blocking off each entrance to the lands.

To maximize your day at Disneyland and successfully execute a "rope drop," the best time to arrive at the security checkpoint is at least 45 to 60 minutes before the official park opening. For a typical 8:00 AM opening, you should aim to be at the Mickey & Friends or Toy Story parking lots by 7:00 AM. Security and the "Esplanade" usually open around 7:15 AM, and Disney typically begins scanning guests through the turnstiles and onto Main Street, U.S.A., about 30 minutes prior to the official start time. By arriving this early, you can position yourself directly at the physical ropes in the Central Hub (in front of the castle) or at the entrances to Tomorrowland and Adventureland. When the park officially opens, those at the front of the "rope drop" crowd can often knock out 3 to 4 major attractions, like Space Mountain or Indiana Jones Adventure, within the first hour of operation before the heavy mid-day crowds arrive.