I have an alternative career and completely non-quantitative education so the first thing for me (post studying for the GMATs) was to sign up for math classes at UCLA. I took Calculus and Math for Management. I'm not sure this would be helpful to the average b-school applicant-the last time I was in a math class was my senior year of high school in 1997 so I was basically answering some potential questions about a 13 year gap.
The second thing I did was try scouting around for "leadership" opportunities. This was very important for me-as an attorney (I'm a fed) and I don't have supervisory authority over anything even though I am designated as the sr. attorney in charge of a couple of different programs. But that basically means I'm the dedicated advisor, not that I work as a "lead" or anything. Also, I'm legally prohibited from volunteering for organizations that get certain sorts of federal funds, especially for the types of funds I control. Since I had been part of my union and had volunteered for various small assignments on and off for 4 years-I basically went in and talked to the president and vp and told them the next time they had an official board spot, to consider me. Their steward quit and they gave me the job. It ended up being a HUGE commitment, basically a second full time unpaid job as their attorney and steward, but gave me amazing things to talk about on my essays for all the schools-I ended up becoming good friends with them and they gave me awesome assignments like putting me on the negotiations team for the labour management agreement and such. The biggest benefit was really their friendship though-and they wrote me a joint recommendation.
I'm just putting my story out there for other people in the alternative career path boat. Good luck!