There's a few ways to get them:
Organized by skill in one pdf for the whole course (by the guy who created the awesome Memrise Duolingo vocab course): https://www.docdroid.net/JnfmyEV/tipsnotesbackup.pdf
Or Replace your username where mine is for information on your progress and tips and notes, etc. https://duome.eu/teribleteri/progress
The way duolingo has it set up is only on their website, under each skill, click on the circle and then on the lightbulb icon. Do it under desktop view to see everything the duolingo site offers (the discussions, etc.)
The Memrise Duolingo vocab course has almost every word broken up into skill groups, without vocab and you can hear individual words, not in sentences. http://www.memrise.com/course/1031737/
I use all these links as I'm primarily in the app. The duolingo website is my least favourite way to see the tips and notes.