I think this is one reason why doing your design work on pen and paper in a quiet place, before you sit down to write any code, can be a game changer. Thinking on the fly and trying to keep a bunch of state in your head is difficult. Mathematical notation is super powerful and there's a reason it exists—use it!
I also find that some programmers' bad habits naturally lead to "fragmented" thinking or lack of sustained focus. A lot of beginning programmers I encounter are sort of like information mice. They have some specific problem that they need a quick answer to, so they hunt around and scavenge for it, skimming various resources like crazy until they find it. While this works for basic, entry-level work and tasks, the same behavior is a complete achilles heel as you progress in you career and have to solve more complex problems. It teaches you to abandon detailed, sustained, focused thinking and building of deep understanding—the kind that allows you to solve problems in a novel way—for a mode of consumption and thinking that is shallow, fragile, and built upon expectations of instantaneousness and immediate gratification. I realize that having the time not to settle for scavenging is sometimes a luxury, but resist the impulse if you can!
I also find that some programmers' bad habits naturally lead to "fragmented" thinking or lack of sustained focus. A lot of beginning programmers I encounter are sort of like information mice. They have some specific problem that they need a quick answer to, so they hunt around and scavenge for it, skimming various resources like crazy until they find it. While this works for basic, entry-level work and tasks, the same behavior is a complete achilles heel as you progress in you career and have to solve more complex problems. It teaches you to abandon detailed, sustained, focused thinking and building of deep understanding—the kind that allows you to solve problems in a novel way—for a mode of consumption and thinking that is shallow, fragile, and built upon expectations of instantaneousness and immediate gratification. I realize that having the time not to settle for scavenging is sometimes a luxury, but resist the impulse if you can!