Get MaxPass (because you're doing one day, it will save a lot of time). I don't know what kind of tickets you've bought or are planning on buying, but personally I would ignore DCA and just concentrate on Disneyland if you only have a day.
This is a no brainer, but get there at opening. I recommend your very first course of action being to Maxpass an E ticket and then get in line for Peter Pan (line for Pan is easiest at rope drop)
Maxpass all the big E tickets: Matterhorn, Big Thunder, Space Mountain, Indiana Jones, Haunted Mansion (its holiday so line will be super crowded) etc.
You can get a walk-on on Splash if you wait until night to ride it.
Make sure to plan out time if you want to do entertainment stuff like parades, fireworks, Fantasmic etc. and keep in mind that getting good viewing spots for these (especially Fantasmic) will require camping out early.
Also see this list I made in a previous thread of exclusive Disneyland attractions:
https://forums.wdwmagic.com/threads/help-planning-disneyland-trip-2-days-or-3.928631/#post-7771551
Above all, don't settle for super long lines. It's kind of like the "buy low, sell high" principle in investing. Ex. if the line for Pirates is 1 hour or above at 3:00 PM, don't do it. You can wait until later and get a better queue time. I sort of map out time at Disneyland like this: opening - noon is fine, noon - 1:00 PM is getting more crowded, 1:00 - 5:00 PM is hell hours (at this point you will have to bite the bullet and wait long standby lines for some attractions), 5:00 PM to close it gets progressively less and less crowded.
(By the way, it sounds like I'm actually going to be in the park the same day as you)
