Develop your chosen Idea
Now that you have chosen your best idea/best aspects of several ideas, develop a more detailed design for your product by drawing it in Orthographic views.
By drawing your product to scale, you should have a clearer idea about the dimensions of the product and how it will actually look once made. This process may also highlight any flaws in your design so that you can make modifications to compensate for this.
Please see a student exemplar below: