Scaling up vs. risk management post-learning curve

Been trading for about a year now, mostly paper, then micro-lots to get a feel for real capital. My win rate's decent enough to be net positive, but when I try to scale up position size, even slightly, it feels like my risk management goes out the window, and I start second-guessing solid setups. It's like the emotional element just amplifies disproportionately. For those of you who've successfully moved from smaller to larger capital, what was the biggest hurdle, and how did you practically overcome it without completely changing your core strategy?