Palm plants are tolerant of being under watered, but they will grow their best when watered on a regular basis. Ideally, palm plants prefer it when their soil is kept evenly moist, especially during the summer months (their active growing season). Allow the soil to dry out only slightly between waterings in the summer. During the winter, you can let the soil dry out a bit more between waterings. Be very careful not to overwater though.
Palms love bright filtered or indirect sunlight. Palms can suffer from too much or too little light. Keep them in the balcony or near a window with bright light. Use fertiliser sparingly in summers only.