Let's describe the role of the builder. Unless you're dealing with a very small project, the contractor functions (i) as a BROKER of the required trades (ie, plumbing, electrical, drywall, roofing, etc.) and (ii) and a SUPERVISOR/COORDINATOR of said trades. The contractor will provide a superintendent(s) to coordinate the micro (fit, finish, three week look-ahead schedule, materials, deliveries, permits, inspections, etc) on the job site and a project manager(s) to coordinate the macro (bidding, contracts, insurance, coordination with owner, etc). The contractor likely DOES NOT employ the tradesmen doing the actual construction.
So as a young architect going to a construction site, a good indication of the quality of the contractor is the condition of the site....
1. Is it clean? "clean" is relative to the stage of construction, but scrap material and trash scattered around the site is an indication the superintendent doesn't control the subs. It's also dangerous, which means the superintendent isn't being supervised.
2. Is it safe? Look for fall hazards that don't have barricades, workers without hard hats, overflowing trash containers, dangerous scaffolding, etc.
3. Is it productive? Look for workers actually installing material (screws, nails, welding, etc). If you see lots of people walking, they are wasting time.
So, the key to good building is the superintendent. In this business, the squeaky wheel gets the grease as the subcontracted firms are balancing workers across multiple projects. A good superintendent will push the subs. A bad superintendent will let the subs work their own schedule with whatever staffing they wish. These jobs are always slower with lesser quality than a driven job.