When designing a part for high volume manufacturing add “machining locators”. These are added to castings/forging/extrusions or can be added to parts machined from billet in the first operation. Through the machining processes they are used to “hold on” to the part. The can be cut off if needed in a final operation.
Consider “Clinching” as opposed to Spot Welding, Riveting and Adhesives. Clinching is a non-heat, non-pierce operation. Joints are watertight, dissimilar metals can be joined and clinching can be done on pre-painted parts.
Always attempt to use connectors with “built-in” strain relief. If not available for your application consider over-molding first and last heat shrink. In addition design an “S” bend into all harness joints to provide strain relief. The number one failure mode of cable harness is wire to terminal connection. Pull force, vibration and bending all can damage these joints. Worst still these are typical intermittent failures which are extremely hard and expensive to diagnosis.