Cockroaches love moist, dirty environments. Give the kitchen a thorough clean regularly. This would involve cleaning behind larger as well as smaller appliances such as the refrigerator, oven and dishwasher. Clean kitchen cabinets and the area under the sink. Bathrooms need to be also kept clean and, as much as possible, kept dry. Crawlspaces are another area you might find them.
Try to eliminate anything that will attract cockroaches. Place food items in tightly sealed containers. Try to have a secure lid on the trash can and don’t leave pet food out for very long. Cockroaches don’t like well lit areas so it might be a good idea to keep lights on at night.
Remember cockroaches enjoy areas with a lot of moisture, if you have dripping taps or any leaking pipes, try to remedy the problem. If you see areas that might be points of entry for cockroaches, seal them up.
While you would need to have the home treated first for a cockroach infestation, boric acid placed in areas where you have seen signs of them can help keep the infestation under control. Keep in mind, though, that with particularly bad cases, you should consult a professional pest control company who can give you further advise.