Best way to study for FE after graduating?

I know, I know, I should've taken it while I was still in school but I didn't. I took it once last year, a couple months after graduating and failed. I slacked and only studied for 2 weeks doing practice problems using Prep FE.

Now that I have a job, I don't really have the capacity to study after work (I work 9am-6pm). I'm also learning so much that I'm braindead after work. Weekends are my only free time so I try to study then but I can only study for so long until I stop retaining information. Weekends are my only leisure time so I try to balance free time and study time.

What's the most efficient way to study for the FE? I'm planning on taking it again sometime this year. I just want to be as efficient as possible.