Go to the poorest parts of where you live and visit the parcs, homeless shelters, pharmacies, obvious trap houses (druggies walking in n out, drug paraphenalia on the floor (baggies, syringes, burnt foils etc), if you see a guy with a banana bag talking to a druggie and them exchanging things just walk up annouce you are trying to buy "x" drug (just say it casually and dont be scared or stressed it will make you look like a cop or a guy who can be overcharged easily) btw try using any local slang for drugs, dont use google, learn about it from experience. Try making friends with bums and lowlifes, they will help you score better drugs and it's generally alot more fun, just be carefull because you can get fucked over pretty easily, like dont trust them with anything such as being on time, having money, not stealing from you, not snitching on you, etc.