Don't write your slides the day before you're giving a presentation!
(I promise this is the only slide I'll use the word 'don't' on.)
Technical presentations can be an exception to this rule sometimes.
It's hard to make a good story out of code examples.
Slides that work as reference tools are great!
If you want slides that work as notes, make a second version of your presentation available, with notes.
(Don't forget remotes and people in other offices.)
Nobody ever is going to get an exhaustive understanding of a topic from a short (or even a long!) presentation. Ever.