every time after having food i do the dishes. i go into detail when cleaning the kitchen board from breadcrumbs and poppyseeds. those bastards should not feast on the tiniest leftovers of my breakfast! as soon as i am finsihed with cleaning a hole catches my attention: the drain. there was sth about roaches liking water and coming out from waterpipes and drains…
keep the place dry and crumbless. that’s a good beginning. they will go to live with the neighbour.
if you want to kill more and maybe catch the mothers, you should turn out the light and come back fifteen minutes to half an hour later ready to stomp, stomp, stomp, all the roaches running around.
your chances of getting rid of them altogether (without putting enough chemicals into that apartment to kill you as well) are slim as they will just reinhabit from next door and the floor above.
i think some cats are extremely roach aggressive. have a search. i might be wrong.
so yes, spic and span. all food kept in the refigerator.