Orginial brainstorming with sketching on a white board or on paper works well.
But I agree with the other designers, if you create your parts and assemblies in CAD, then you will be so much better off in fit. You can check interference in SolidWorks between components and simulate how components are assembled.
I see you are from MN. There is a southern SolidWorks Minnesota Users Group
http://www.swugn.org/pages/calendar/calendar.html that meets in February. There may be some engineers there that can give you suggestions. SolidWorks users are very helpful to each other - no matter what their age. It may be too late for this year but you have to think about the future. Marie