Concrete does not crack because the mix was bad. It cracks because something under it moved, or because nobody gave it a place to crack on purpose. Both of those are decided before the truck shows up.
Base comes first. The ground gets cleared of organics, graded to the fall you want, and compacted in lifts. Soft spots get dug out and replaced with stone rather than filled with dirt and hoped over. In our clay soils around Raleigh and Johnston County, this is where the money should go, and it is also the easiest place for a cheap bid to save money you cannot see.
Then thickness and steel. A car driveway wants four inches; anywhere a loaded truck or a trailer will sit wants more, along with rebar rather than just wire mesh. If a contractor quotes the same thickness for a parking pad as for a walkway, ask why.
Control joints are the part homeowners notice least and matter most. Concrete shrinks as it cures, and it will crack. Joints cut at the right depth and spacing decide where that crack goes, which is why a well-done slab looks like clean straight lines instead of a spiderweb.
Finally, curing. Fresh concrete that dries too fast on a hot Carolina afternoon loses strength at the surface and starts dusting and scaling later. Keeping it wet or covered for the first few days is free, and it is the last chance to protect everything you paid for underneath.