I've got a treasure trove of design guides. Even when you are super comfortable with a process (like injection molding) I find it good practice to use them as a low-cost checker.
So i figured I would share one of my favorite design guides, the GE Engineering Thermoplastic Design Guide.
It's a concise, 15-page guideline that touches on wall thickness, parting lines, ejection, appearances, ribs, gussets, bosses, holes and depressions, and fillets & corners.
When I mean concise, I mean concise, every guideline looks like this...
Even if you don't have time to check it out now, do yourself a favor and download it for later.