Roaches are omnivorous and seek dark, moist places . Inspect areas around the baseboards of your floor, under or around pipes, anywhere there is food waste, behind electrical outlet covers, and narrow, hard to reach spaces are ripe for potential infestation. Roaches prefer to leave their eggs protected in dark crevices if they are not viviparous or oviparous. You can do this by blowing a portable fan around the area to provoke an escape response, or by using an intense sudden light source to provoke the escape response . Leaving bait out without any pesticide is not recommended, as it will simply encourage infestation. These are areas with regular food contact, exposure to water, or that are dark and inaccessible. These areas should be targeted regardless of observed infestation. Boric acid has a strong prophylactic effect that kills generations of insects over time. Cockroaches have a number of scent glands used in communication and courtship that produce a distinctive smell, in some cases sweet, in others oily and musky. These are telltale signs of an area that is infested and should be targeted. Some cockroaches are perching insects that can thrive on top of high surfaces like shelves, and these should be inventoried and cleared for application of the insecticide. Make sure this is done before preparing or applying the insecticide. Clean surfaces and preventing standing water from building up deprive cockroaches of resources. Bait is unnecessary with this insecticide, and eggs are less likely to be spread where there is no feeding resource for the female insect.

TL;DR in Vietnamese:
Kiểm tra những chỗ có thể là nơi sinh sống của gián trong nhà. Kiểm tra những khu vực này để tìm dấu hiệu xâm nhiễm của gián. Lưu ý những khu vực có thể có gián sinh sống, ăn uống hoặc đẻ trứng. Kiểm tra những nơi gián có thể sinh sống qua mùi hôi của chúng. Làm vệ sinh những nơi có vụn thức ăn rơi vãi hoặc có nước đọng.