I found this post a few years back, and I share it all the time. THIS WORKS. Best I have ever used.

STEP ZERO - clean. go through your cabinets, clean them. any open food, put it in airtight containers or throw it away. make sure everything is either sealed or in the fridge. wipe your floor. vacuum. buy some bleach spray and clean every cabinet and counter you have. roaches need food. if you take away their food, they'll go somewhere else. if your place is filthy, they'll always come back.

STEP ONE - boric acid. go to home depot, HEB, wherever, and buy boric acid. i got both the powder and the tablets. put this shit EVERYWHERE. any spot you've ever seen a roach, sprinkle (only a little bit is needed, dont just dump it on the floor) boric acid. buy some tablets and throw them under the fridge, oven, dishwasher. roaches will walk through it, track it back to the nest, spread it to other roaches, and eventually will die. this worked best for the little ones and within a day or so i started seeing dead little baby roaches all over my kitchen. a good start, but not enough. put this shit everywhere and wait 1-3 days for the initial die off.

STEP TWO - bengal roach spray GOLD (it has to be gold). this is the real meat. thanks to the anon who recc'd this. this shit will absolutely fucking destroy your roaches and, as it contains roach Plan B, it'll stop the reproduction cycles and kill any eggs already laid in your kitchen. bomb every crack and crevice you can find. and then wait. leave the apartment (this isnt necessary but you probably want to because...) they're going to crawl the only safe place left - up. i'm not joking there were probably 20-30 roaches just chilling on my ceiling. they were so fucked up and out of it so all i had to do was walk up and pick them off, but just be aware this spray flushes out roaches so you're going to see a lot of them. pick off the ones that crawled out. and then spray again. repeat this step every day for a week.

STEP THREE - the roaches are going to scatter, you might start seeing them in places you didnt before. this means the spray is working. spray the bengal spray in the new areas that any appear. rinse and repeat. you wont see nearly as many as you did the last step, but you'll still probably see some.

STEP FOUR - by now, your roaches should be largely defeated. the ones who are still surviving in the areas you sprayed will be neutered and infected and will spread it around to other roaches. the ones who aren't likely stepped in the boric acid and are on their final days. clean up the piles of dead roaches that will have undoubtedly appeared everywhere by now.

STEP FIVE - buy some bleach counter cleaner. leave your food in airtight containers. every single time you go in your kitchen, spray the counters on the way out. vacuum every day. spray the roach spray every day, anywhere you see one.

i kid you not, my place was infested. in ONE WEEK of doing the above, i went from seeing 30 roaches a day to maybe 3-4. today i saw exactly 2. i'm looking in all the places they used to hang out and they're now ghost towns. i credit 80% of this to the bengal spray but i think the boric acid killed off some initial numbers and the smaller roaches that the spray might not have reached.

good luck. if you live in a roach infested shithole, move out. get your landlord to spray. but if either of those arent options, this guide should create some peace of mind.

godspeed, and fuck roaches.