Light
Haworthias are reasonably adaptable plants that that will take various light conditions, but neither direct sunlight or deep shade. Direct sunlight will make the leaves of all Haworthia’s go an ugly red, purple or brown colour. Move to a shady spot and if the damage isn’t too bad these colourings will fade over time.
Watering

A surviving plant will get by with watering just once a month, however to get the plant thriving it will need to be done at least once a fortnight, possibly once a week in very warm temperatures.

Either way, water well and then only water again when the soil has largely dried out. These plants are very tolerant of underwatering but will succumb quickly to rotting if overwatered.

Make sure you try your best to keep water out of the crown or rosette of the plant, in cool temperatures doing this will again encourage rotting.
Humidity
As is common with many other succulent plants humidity is not important. However, they do like good ventilation so avoid very tight “airless” corners of your home.