First of all, you can according to the schematic diagram will be the components An functional arrangement, (the analog and digital circuits are separated), so that your board all day long will look a little tidier, when necessary, you can be some integrated chip taking pins reset, in order to reduce the flying wires, but also make the layout of the layout is more concise and more intuitive. Admittedly, experience is important in this regard, but I personally think having a good wiring specification is more important.