So for me Sephora, Macy's and Nordstrom were who got most of my makeup money. Now I am a lot better about all of them! I can go in and look at things I just make a battle plan first.
In example: I wanted to swatch UD Venom the other day because I was thinking of picking it up in a sale, at the same time my SO (who is helping me with my lowbuy) wanted to see the eyeshadow I was buying to potentially talk me out of it. So we went to Sephora. I swatched the shadow and he remarked that it was definitely not like anything he'd seen me wear before, it was really pretty (which is a huge compliment from him) and that it seemed like a good purchase. Then I swatched Venom... It looked just like my MAC rebel - which I just got rid of several dupes for. I was sad. SO said we should go to Macy's and swatch the Rebel to make sure it was similar, we went there and I swatched rebel (which yeah Rebel and Venom are slightly different but not enough for me to not call them dupes) and I showed him Cyber because I want it.
TLDR for the example if I go into these 'high-risk' stores with a plan IE only swatching a specific item, I can get in and out without a ton of browsing which keeps me from making impulse buys.
What used to be low risk stores have become the danger zones for me now. I keep trying to justify drugstore makeup as okay to buy because it's so cheap it 'doesn't really count'. So I have been avoiding going to drugstores, box stores ect or when I do go avoiding the entire beauty section. It's dead to me!
Internet shopping... this one hits close to home. I used to order so many packages that my mailman asked me if I ran a business out of my house. I let myself browse and shop and cull a cart. Then I make myself cancel said cart. Sometimes that is enough, I got to shop and imagine but without the guilt. When I cull the cart I really analyze the crap out of everything. If I am still thinking about it when I can buy makeup (based off of my lowbuy rules) I can get the item but honestly, I normally forget about it within a few days.