You can reassign up to 100000 surplus skilled people (managers, high tech, teachers, medical) a month to work as ordinary low, medium or high level workers.
If you're not planning on using your military any time soon, try deactivating as much of it as possible. The freed-up officers and soldiers will become middle level managers and low level workers, respectively.
If you look at your population, you'll see large numbers of housewives and disabled people in the 21-65 age brackets. You can convert some of the housewives back into working people by changing some of your universities into back to work schools. You can do the same with some of your disabled people by converting hospitals into special clinics. This will create more low level workers, among others.