I'll admit I've never sat in the left seat (for want of money, nothing else!) But I do have a commanding experience of checklists. A nice idea is to put a question mark after every item on the list. so instead of "Gear Down" it's "Gear Down?", flick the switch, be sure it worked, and then "Yup". And something I think we all do it with checklists (and if you don't then DO!) is say it out loud (yes even when on your own).
As for memorised checklists, I'd say have the list open on your lap for safety, and add an extra thing onto the list. "anything forgotten?" where you give a quick look down to your checklist and count the steps
Another good idea is numbering the steps as well.
These are nowt but things I've done at my work, be it at study, or shop management