I have a friend going to Disneyland for the first time with her family and I thought I'd write this up for her. Feel free to leave a comment with more advice if I missed something.
Start the trip off with a train ride all around the park. This way you can really get a feel for the park and see the layout.
Make sure to watch Fantasmic! at least once. Preferably earlier in the trip than later. That way you can go again if you want to.
Go on the Haunted Mansion ride at least one time at night. It's more fun to come off the ride into the dark.
If you see the line for Indiana Jones is not too long, go on it! That ride breaks down really often, so go whenever you can.
Don't bother standing in the line for the Finding Nemo submarine ride. Go to a cast member there and ask to go into the room they have for people with claustrophobia. It's the exact same experience, and takes a fraction of the time. Those lines are ridiculously long!
Eat a snack in the morning and go on the big rides before it starts to get really busy. Eat breakfast later when the ride lines start growing.
If possible, try to watch the latest Disney and Pixar films before going because these will have a high presence in the park.
Hydrate, hydrate, hydrate! If driving, buy a case of water bottles to take with you and refill them instead of buying them in the park. At almost $3 to buy a bottle in the park, this will save you tons of money. And with the heat, you will need to drink more than you think you will.
If you do Toon Town, do it early in the day or later at night. It gets really hot and crowded there during the day.
Study ahead of time and make sure to take advantage of the Fast Pass system.
Make sure to see Billy Hill and the Hillbillies at the Golden Horseshoe at least once.
When you go to Disney California Adventure, go right when it opens, and head directly to Toy Story Midway Mania. This is the most popular ride in the park and the line is always long.
On Main Street, use the reader board near the entrances to the other lands to see the wait times for rides. These are pretty accurate.
The kid's meals are usually big enough for an adult, and come with a drink. This is a great way to save money.
On the first day, go to the World of Disney store in Downtown Disney, or Town Hall in Disneyland and get a "first trip" pin. They are free and make great souvenirs.
Make sure to clear out all bags of any pocket knives or glass bottles, as those will be confiscated by security at the bag check station.
Have your photo id ready along with your passes to get into the park as quickly as possible.
Always get a hand stamp before leaving the park!!! This is imperative!
Must Eats:A churro, a corndog, caramel apple(ask for them to cut it into slices for you,they're easier to eat that way), Dole Whip, Bengal BBQ skewer, and my personal favorite: a Schmoozie's Smoothie.