When it comes to growing anything, it’s all about water. You want to catch every drop of it. Moisture in the soil builds organic matter and fertility, which equals naturally healthy plants. Regardless of what you intend to grow, shaping your landscape to harvest the water is step one.
Contrary to modern landscape design, that does its best to get rid of water as quickly as possible, we want to look at our homescape as a mini-watershed where not one drop of water is going to leave. This goes for the overflow from the neighbours too; that problem is about to become a solution.
So what does this have to do with creating a planting bed? Everything: you want your beds to water themselves and pump fertility, naturally. Most raised beds you see are boxed up, and while that is a step in the right direction, you are still missing the flow.