I have always believed that the best place to start when designing a new feature or product flow is with a pen and a piece of paper. I think if you go to quickly to screen/UI design, it’s harder to take a step back to focus on the actual user problem. Instead, you immediately start thinking about pixels and your thinking is by default limited to your current UI.

I just came across these printable sheets for wire-framing by hand. It’s been put together as a side project by Pasquale Vitiello.

You can choose Mobile devices, tablets, desktops, or even just plan grids.