Write out the signal chain as a reference for the order of the parts. The order of the components influences the function of the circuit. Mini guitar amplifier signal chains typically begin with a power supply in the form of a 9-volt battery, a 1/4-inch balanced input jack, followed by the circuit board itself, which includes resistors, capacitors, op-amp chip and transistors and a speaker.
Draw a large rectangle on a separate piece of paper to the signal chain sketch. As well as providing a neat frame for the schematic diagram, the rectangle itself denotes that yours is an integrated circuit and that everything inside the rectangle forms part of the same system.
Draw the component symbols inside the rectangle. For example, to illustrate a fuse, draw a narrow rectangle whose height is approximately a quarter of the length with a horizontal line through the center of the rectangle. To illustrate an inductor, draw a horizontal line, joined to a series of four "arches," joined to a second horizontal line of equal length to the first. Refer to a trusted resource if you are unsure of any schematic symbols. Reference your signal chain sketch and plot the corresponding symbols from the sketch inside the rectangle, in linear order from left to right (See References 2). Although the physical circuit may double-back on itself, schematic diagrams start on the top left and continue in a linear fashion to the right. Draw each symbol as clearly as possible.
Write component values next to the relevant diagram. Some components, such as resistors and power transformers, have specific values. In such cases, simply denoting the component isn't enough for a complete schematic, you must also indicate the value. Indicate the value of a resistor in Ohms and use "K" to represent thousands, for example "12k Ohms." Indicate the value of a power supply in volts.
Illustrate connection methods. Use horizontal lines to illustrate wires. Draw a solid dot over wires connected to each other. Connections should be clear and unambiguous. Some wires may cross but not be connected. Illustrate this by joining the two parallel lines with a horizontal line. Mini guitar amplifier chassis-mount components such as speakers and jacks are typically wired this way.
Draw a key so that other people know what each schematic symbol represents. Start with the most common component in your schematic. Draw the symbol on the left and write the name of the component on the right. You may wish to list a spec for certain parts, for example "6L6 power tubes."