The earlier the better! But there is no need to arrive SUPER early, as that would a waste of time (for sleeping!). It depends on where you are going. For example, if you are going to RSR or Peter pan, then you would need to arrive earlier than if you were going to say, pirates of the carribean first thing. But keep in mind that PP and RSR will have already built up long lines due to EMH guests already in the parks. Try to arrive at least 30 minutes in advance. To be even more up front, arrive 60 minutes in advance, and you will not find many non EMH guests around earlier than that. So you will do great with 60 to30 minutes before opening.