We just got back from a week in Southern California which included 3 days at Disneyland/California Adventure and a day at Universal Studios. If you are planning a trip there anytime soon, I have some words of advice for you.
#1--Take a cattle prod with you. If you don't have access to one, buy a light saber, sword, or magic wand--anything long and pointy will do--so that you can poke and move people out of your way.
I don't know what it is about the Happiest Place on Earth, but people lose all common sense when they arrive. The people pushing strollers will abruptly stop whilst a stampede of mouseketeers is behind them, causing a bottle neck. Groups of 3or more will all walk abreast of one another, usually holding hands and strolling at a snail's pace, meaning NO ONE can get around them. My favorite (note sarcasm) was a group of 3 people who came to a dead stop outside of Star Tours (the MOST popular attraction this summer), each pulling out a map and opening it is far as possible, to figure out where they were, or where they were going. These instances are when the cattle prod will come in most handy.
#2--Wear clothing that actually fits your body. Oh my goodness, if you are into people watching, Disneyland is THE place to be. I do not understand the phenomena of women wearing clothing several sizes too small for their bodies. This is another instance of when the cattle prod will come in handy. You can jolt all of the people who come to a dead stop to gawk at these women right out of your way.
#3--If you are young and in love, please spend the admission fees to get a hotel room instead. My child and I do not enjoy standing in line behind you while you grope and squeeze and slurp all over one another. It's Pirates of the Caribbean, NOT Love Canal.
OK, now for some serious tips:
If you have a Smart Phone, download MouseWait. THE best app for looking up wait times, seeing if rides are closed, etc. Couldn't have lived without it.
Figure out the Fast Pass system. We rode 17 rides on Friday, mainly due to these handy little passes. I'm not sure how I worked it out, but I did.
Go early, ride as much as you can, leave after lunch, go swim, take a nap, refresh, and go back around 6. When everyone is watching the parades, river shows and fireworks, you can ride lots of stuff without waiting.
Wear comfy shoes. I wore one pair in the morning and switched to something else in the evenings. I only got one blister!
Finally, if you run hot like I do, the following places are very well air conditioned: Space Mountain once you get inside the lower part, Pirates, Haunted Mansion, Soarin' Over California, and Buzz Lightyear. The number one coolest place in all of Disneyland is inside It's A Small World. You will be singing that song in your head for the rest of the week, but it's worth it for the cool air!!