I'm in a similar boat. I'm in a graduate program at a difficult university, and as such my time is often exhausted with school-related work. That being said, the difficulty and amount of written material has greatly improved my reading abilities.
Here's my strategy:
2 practice tests per week, taken in non-optimum conditions (a noisy, busy coffee shop with kids scurrying, people talking, etc.) I'm doing this to train my ability to focus with outside noise and such. I could keep taking my practice tests in the comfort of my own home, but I don't think that the testing center will be that quiet.
Of course, I only take the tests timed, as well.
On other days, I've been working on the LG Bible. I'll be through with my first go-round of that in probably another week or so, when after that I'll be working on the LG Bible.
Btw, I'll be taking the test in September too. Personally, I'd be flipping out if I was taking the June test and hadn't started preparing yet. Good luck.