One of the most important things I've found is their need - and this is a must - for a sand substrate tank. I recently changed my tank from sand to small rounded quartz - and they hate it !
Where they used to be completely hidden in the sand and I never saw them, they now "sit" on top and are looking very much displeased.
So I'm going to be rehoming mine to someone's sand tank - hopefully soon.
So for their happinss and well being, above all it's sand.
As for food I feed a mix of flakes, granules, sinking / algae and carnivore wafers / pellets. Plus the occasional (thawed) frozen bloodworm, on whic mine seem to be doing very well.
But I would say due to their shy nature, they should be kept with gregarious fish that will gobble everything up before they get a chance to come along.