Well, step 1: Concept(s)
Step 2: identify common and essential skills: trim to 5-6, and put them in service skills.
Step 3: Identify other key skills for the specialties, put into the specialty tables
Step 4: think about the risk level of the career, more risk, harder survival, and usually, better benefits
Step 5: start filling in the events table.
Step 6: start guestimating the other rolls (Enlistment and Promotion), and filling in extra skills that become evident.
More polar results on a 2d6 or 3d6 should have higher risk and/or reward.
Go back and touch up; skills that would be more common get additional placements.