I'm working to plan my garden now. I've got a few plants growing now, some lettuce and spinach. I have done some soil prep in the other beds, so I am ready to put some seeds in the ground. You wouldn't think that planning a garden is that complicated, but I find it to be.
You need to consider the obvious things, like the hardiness of the plant. Some seeds can't be sown until after the last frost. But then you need to consider what was in that garden bed previously. You want to rotate crops so that you don't deplete the soil. You also have think about the life cycle of the plant. Some veggies will bolt when the weather gets hot. Others just get going when the weather warms up. This means that some garden beds will be available for new crops in the middle of the season. Need to plan for that too.
Last year I had pumpkins that ripened too early. I picked them in August, not when you want them in October. So I'll be sowing my pumpkin seeds later this year.
Another consideration is wildlife. My garden fence is pretty good at keeping the varmints out. But one year my corn was just ready to pick, when I saw that racoons had climbed in and helped themselves. So now I try to hide the corn patch behind other plants, so the racoons can't see it so well. That strategy has worked for a couple of seasons.
So, I'm learning by trial and error. But I do enjoy the taste of garden fresh veggies!