For me, the key is good soil.
In the last photo above, (bottom pic) you can see one of the hanging pots. we use the coconut husk lining, and then, the soil is good, compost, plus whatever the plant come with. It's about 16-18 inches (a little under half meter) in diameter, the hanging pot. the thing with the coconut, is great drainage. AND, I try and water the Raspberries and strawberries most ever day... some days, if it is hot, water early morning and later, close to dusk.