There are three tiers of workers (as is everything else); tier 1, 2 and 3. What I am having a hard time with is figuring out what I can build to target workers from each of the tiers. I gather what I am sure everyone else has, low tech industrial (regardless of density really) provides mostly tier 1 jobs.

But what are my other building options for tier 1 jobs? If I want to target tier 2 or 3 what types of buildings should I consider?