Relax.
Have fun.
I know it’s outrageously expensive to go to Disneyland, but I’ve personally seen it many times – people want to ‘get their money’s worth’ – but it ends up stressing people out.
Just take your time. Don’t worry about long lines or crowds. Once you walk under the railroad bridge after you get through the Main Entrance, just absorb. Notice the detail in everything.
You can plan out what attractions you want to see, then go see them. And if you don’t get to see/do everything, don’t worry about it. Disneyland isn’t going anywhere. It will be there the next time you visit.
And if you’d like to truly experience how Disneyland started, and what it’s really about, hire a personal Tour Guide who has the experience to help guide you on your visit. Former Disneyland Tour Guides can be found online for hire, and they cost a fraction of what you’d pay to Disney.
Original Quora question – What are the most important things to know when visiting Disneyland?