I watched all the video tutorials for the Pro Exam and took notes in the app when I came across new/unfamiliar concepts. I watched the labs but did not complete the steps myself. I took the LinuxAcademy exam 3 times and ensured I understood why the answers were what they were. I didn't spend much time with the required reading whitepapers - the only one I really read in depth was OpsWorks because it was very new to me. Finally, I took the exam just a day or two after I finished studying, so everything was fresh in my mind.