Some of this has already been said:
- Start early. If you have early admission, use every minute of it.
- Stay hydrated
- Bring drinks and get cups of ice (free) - saves a ton of $ especially if you drink soda. But if you drink soda, make sure you also drink water.
- When you feel tired, take a break, especially if you have kids - for there will be much misery if people get tired and cranky
- Use FP to their full potential - which means always have at least one "connected" (so WOC doesn't count) FP in your possession at all times. Better yet - hold FP for E-tickets from both parks at the same time (but requires a runner)
- Hit fireworks as early in your stay as possible. They get cancelled at the slightest wind (e.g. tinker bell farts)
- Don't wear new shoes - this isn't a time to break in new shoes. We walked 30k+ steps / 15 miles per day.
- Sunscreen and hats
- Wish people wearing happy birthday buttons a happy birthday. Spread some love.
- Use the Disneyland app to get wait times and FP return times.
- Bring a battery tank AND run your phone in low-power mode
- Get a Disney VISA card. Use it before the trip to get the promotional gift cards ($250). Use it during the trip for M&G and store/food discounts.
- Fire hydrant (blue FP zone) view for WOC
- If you have young kids, bring them to a cast member, show them the CM badge, tell them if lost, find someone with one of these badges
- Take photos of your park admission cards (card ID numbers) in case they get lost