Real-time search and favorite lessons
5yr
 Lai Yu-Hsuan 
I've got two ideas on how to make it easier to navigate this site:
1) Real-time search. Display the most relevant results under the search bar while the user is typing. It can introduce some extra loading on the server-side, but I think it's not that bad considering the number of lessons are rather manageable (even if Proko turns into the biggest art education site in the world, I doubt there will be more than a hundred thousand lessons). 
2) Favorite lessons. Let users save a lesson into a "favorite" tab (probably accessible from the dashboard). Some lessons are more likely to be re-watched than others. I personally watched the gesture lesson for about 10 times.