What is stray capacitance and how can it be minimized ?

Stray capacitance is unintended and unwanted capacitance in a circuit.

Capacitance doesn't exist only within capacitors. In fact, any two surfaces at different electric potential, and that are close enough together to generate an electric field have capacitance, and thus act like a capacitor. Such effects are often present within circuits (for exampl,e between conductive runs or component leads), even though they are not intended. This unintended capaictance is referred to as stray capacitance, and it can result in a disruption of normal current flow within a circuit.

Designers of circuits try to minimize stray capacitance as much as possible. They do this by keeping the leads of electronic components very short and grouping components in such a way to eliminate capacitive coupling.