If you can, take a look at how previous projects were started and run (if any).  It sounds like you will be doing a bit of outsourcing so there are some key steps you will need prior to finding them.  I would strongly suggest documenting the information as you will need to be able to refer to it throughout your project.

You have a design in mind.  Will the marketplace support it?  You will need sales and marketing input to determine the viability.

If yes to the above, what are the defined requirements for the product?  This information will be critical to any resources involved in the project.  Be diligent up front as changes get increasingly expensive as the project progresses.  If there is proprietary or new patentable technologies involved, an attorney would be useful.

What resources will be needed for this?  You indicate outsourcing board design and some CAD work so there should be someone to coordinate that aspect.  Others include finance, materials procurement, sales & marketing, manufacturing, service and compliance.

Once you have the requirements and needed resources identified, then you can look into the timelines for running the project.

There are numerous books and web information on project management as well as software to assist in tracking and coordinating activities.  Not all may be applicable to what you are doing but I would recommend doing a bit of searching around and you may find a few things that you can pull out of various books etc to "customize" a procedure appropriate to the business.

Good luck

A really big thing that PSE points out is define the requirement.  A project with an ill defined requirement will never go well.  To me that's pretty much Design/Project management 101.  In your case as PSE stresses it sounds like part of this is confirming that there is a need/market for the product.

I'd then try and created some kind of what we used to call 'Statement Of Work'.  Essentially what work needs to be done to create a design that meets the requirement and get it proven and ready for production (or even into production if your responsibility goes that far).  

Don't forget any regulatory compliance, drawing/design checking, testing, configuration management etc. requirements and to have the work in the SOW.  

I’d then look at assigning labor & costs to the various tasks that come out of the SOW.  This will give you some idea of the work involved and how many ‘man hours’ it will take.

I’d then look at creating some kind of schedule or time plan for the project.

I’d then think about doing some kind of project risk analysis, what could go wrong, how likely is it and what effect would it have on cost, schedule and performance.  You’d then want to have some kind of risk mitigation plan, especially for anything high risk.

For all subcontractors you’d want to create some kind of Statement of Work for them to formalize what you expect from them.  You may be able to use the statement of work you prepared and just refer them to the relevant sections or you may be better creating a SOW for them.  Don’t forget to put things like what format you want the resultant design data (drawings, models etc.) in and if relevant if you want them to use your companies document format & numbering scheme etc.  Not sure it’s an issue for you but do you need them to provide some kind of ‘interface’ drawing and/or simplified model to feed into higher level product documentation or give to customers for design guide purposes.

The above is just my opinion based on my experience, I’ve probably missed things and others with perhaps more experience may have other ideas.  Also I’m not electrical so there may be things from an electrical point of view that needs more attention.

Hope it helps.

Ken