Things that you should not do with younger children at Disneyland:
Don't wait too long in lines.
We decided that Genie + was a must for our trip to Disneyland and Disney's California Adventure. It allowed our family to ride attractions with less wait time. My boys had a hard time waiting for more than 30 minutes for any attraction, so I tried to use that as a general rule of thumb. If we could get a Genie + lightning lane, we would do our best to use it. That being said, not all rides utilize Genie + at Disneyland, which brings us to the next suggestion...
Don't focus on the middle of the day... Instead focus on the morning and evening.
Using the first hour or so of the day really helped our family enjoy the park. We were able to go to places like Toontown and Avengers Campus early in the day, ride a few rides with shorter wait times, and enjoy the ambiance before those locations got too crowded. We got them up early for rope drop, but we knew that the lines would be shorter after dinner. In the middle of the day, we focused on resting, eating, taking a nap, and getting ready for the evening. Our kids were troopers during our visit, and I know that won't work for everyone, but if you can get some rest in the middle of the day, the evening times can have shorter wait times.