Rule No. 1: Do anything you can do to give your weed dealers less reason to be paranoid, and their neighbors less reason to be suspicious. Your dealers are going to be as paranoid as they feel they need to be. Even if you think they are being unrealistic, just cooperate in whatever way makes them feel better.
Don't ask your weed dealer anything about weed via phone call, email, text message, or Facebook "private" message (especially). Don't use obvious slang like "smoke" or "green." Just ask if they're around, and if you can stop by. They're a weed dealer: They'll have fucking weed and if they don't, they'll tell you not to come by.
If you really, really need to talk about weed over various communication devices, come up with a code word next time you meet your dealer. Pick something that might commonly be found divided into portions. Try choosing something which wouldn't be entirely unusual to pick up at someone's house.
If you are around other people, don't mention the person is a dealer. You could be surrounded by rich potheads, or even close friends of the dealer, who you might assume already know—don't bring it up, just in case. And definitely don't give out your dealer's name or phone number, especially without asking first.
Don't fucking ask your weed dealer about weed on the phone! Or by text! GodDAMNit!
Leave your fucking friends at home. Weed dealers don't want to meet new people. If you absolutely must bring a friend with you, have her wait at a coffee shop, or at least in the car, and certainly not standing outside the dealer's front door.
If you know someone who also wants to buy weed, just buy extra for them when you get yours. You can even charge them extra for picking it up for them. If there is a really good reason why your friend must buy directly from the dealer, let your dealer know you have a potential new customer you'd like to bring along with you next time to introduce them. Considering Rule No. 1, you might even give the dealer your friend's full name, so your dealer can look them up on Facebook to see if they seem "cool."
Unless you are close, longtime friends of the dealer, just go in, get your shit, and leave. No, it's not time to try out the product, it's time to let your dealer get on with whatever they had to stop doing to sell you weed.
Unless they offer, your weed dealer doesn't deliver. Don't ask them to meet you someplace—especially in public. Go to wherever they are, or feel the most safe, usually at home.
If parking is difficult near your dealer's house, and you absolutely have no other option than to double-park in the middle of the street with your hazards on, don't do it right in front of their house; go down the street a little, at least. Your dealer's neighbors don't need to know that people are regularly stopping at their house for five minutes at a time.
Don't ask them to weigh out the weed depending on how much money you happen to have brought with you. Nobody likes math. Nobody.
Don't haggle with your dealer. They are putting themselves at risk by having large quantities of an illegal product in their home, and the only reason for this is to make money.
No, you can't pay with PayPal. God forbid your weed dealer gets audited or something and has to explain his/her mysterious source of income. Stick with cash.
Buy in bulk. First of all, some dealers give a price break at an ounce, so that's a benefit to you. But it also means fewer times you're showing up at their house, therefore giving the neighbors less reason to be suspicious.
Bring something discreet to carry your weed home in, preferably something that seals tightly, so that passersby don't smell it as you're walking away from your dealer's house.
If you've agreed to meet your dealer at their house at a certain time, and they aren't there yet, don't hang out on their front porch or with your car idling in front of their house. Go get a coffee or something.
If you show up at your dealer's house and they only have indica and not your precious sativa, or vice versa, just buy the fucking weed, OK?