Probably the most common question about UX is how to start screen design and what principles should we care about? Designing screens starts with sketching. We at UX studio start with quick paper sketches, then build wireframes and clickable prototypes, test them, repair them, and finally get to the pixel perfect, colorful detailed design plans. In what follows we will show you the eight most important rules of thumb which one needs to take into account when designing screens. These are the basics for anyone who is working on designing a digital product.