To water the plant, it is easiest to simply add water into the saucer than watering the plant overhead. Try to maintain at least an inch or so of water in the saucer all of the time or, when the water has just about evaporated, add more. The soil must be kept damp to wet at all times. If you go away on a holiday, there is no harm in raising the water level to the top of the pot to assure your plant won't dry out before you return. But flytraps don't like a permanently high water-table, unlike plants like Sarracenia, which can thrive almost flooded.
Flytraps can rot if constantly waterlogged in an un-drained container.
Most tap and well water contain too many minerals to be used for venus flytraps. Allowing tap water to sit a day or two will only allow chlorine to dissipate, leaving minerals behind, so stick with the purified water. Flytraps enjoy being grown in a partly sunny area. This means that during the growing season the plant should receive about 3 to 6 hours of direct sun. Shade-grown plants will appear elongated, with underdeveloped traps.