Mix baking soda with sugar. Sugar lures roaches, and the baking soda kills them. Sprinkle the mix in their hiding spots.
Neem oil or powder works wonders. For oil, mix with water in a spray bottle and spray where you see roaches. With powder, sprinkle at night and repeat in the morning.
Peppermint oil repels roaches. Mix it with salt water and spray infested areas. It takes continuous use to see results.
Crush bay leaves and sprinkle them in cupboards or where you spot roaches. Or boil leaves and spray the water.