The answer to 'how to kill pest' is to use integrated pest management (IPM) techniques. IPM involves a combination of non-chemical and chemical control methods to effectively and safely eliminate pests. The first step is to identify the specific pest problem, then use a range of prevention and treatment options tailored to the situation.
For common household pests like ants, cockroaches, or rodents, you can start with non-chemical methods like sealing entry points, removing food sources, and using traps. If those don't work, you may need to use targeted pesticide treatments, but always follow the product instructions carefully and take safety precautions. For more complex or severe infestations, it's best to call in a professional pest control technician who can assess the situation and develop a comprehensive treatment plan.