Determine which manufacturing processes make the most sense for your product. For lower volumes or less complex parts, consider vacuum forming instead of injection molding. For some complex metal geometries consider casting instead of machining.
Example: When a metal must be coated, consider powder coating instead of painting. The powder coating process allows for excess powder to be collected and reused in the coating process, as opposed to paint overspray, which cannot be recovered.
Watch out: Manufacturing processes are complex systems, and often energy or materials waste can be hidden within these systems. Talk with your manufacturer to make sure you understand the entire process and consult indexes like the OKALA 07 impact factors table to make sure that all aspects of the process are considered.