I sometimes work with remote designers, so I needed something that is flexible and fast to create.<p>Rather than trying to spend hours using Gimp or Photoshop ( I have been down that road), this is what I do as its much faster to translate whats in my mind to something a designer can use.<p>Get a sketch pad ( blank pages no lines ), I bought mine at a local pharmacy.<p>Get a good mechanical pencil, they sell good ones for drafting, also get a good erasure that is different from the pencil.<p>Get yourself a good ruler, it you want to draw to scale get an architectural ruler not an engineering ruler ( scale is for land etc so its too big ) if you do not need to draw to scale, get a metal ruler with the cork underside to prevent slipping on the paper.<p>Get yourself a plastic stencil of different shapes.  Many of these are used for flow charts or electric circuits, but find one that has the shapes you want.<p>Draw out your proof of concepts on paper using your rulers and stencils.<p>Label your drawing.<p>Finally just take a picture with your phone and send it to the designer.<p>It you have to make a change, its super simple to erase something and make an adjustment.