Make sure while you are prototyping to keep production in mind. If you design for production from the start things get a lot easier as you progress through development to production. That was one of the reasons I can go from concept to production in a week, I would always design for mass production from day one.

Tip: also keep your design as flexible (unconstrained) as possible.

I was doing products targeted towards kids, when Mattel had the lead paint problem the government issued new regulations written by the lobbyists for Mattel. Instead of increasing safety in any meaningful way they just limited any competition by small companies by increased compliance and testing costs drastically. Congress is contemplating a number of other laws that will make it even more of a pain in the ass.