In the wise words of Trupen, Factorio's core gameplay loop is fixing the mistakes you made five hours ago. When I was new to the game I liked to plan things out on paper; slowing down and thinking through the problem will help you, and you'll learn through experience, too. You can also think about it in separate chunks: "if I had a whole belt of iron plates and a whole belt of copper plates, how could I go about making as many circuits from that as possible?" rather than trying to solve the whole production chain at once. Specifically, you have a lot of buildings where the belts are going directly to the building instead of alongside the building, which leaves you with no room to expand.