The Venus flytrap comes from the same Carolina bogs as Sarracenia and wants the same treatment. Most flytraps die from being kept as houseplants — they belong outside.
Light: Full sun, 6+ hours. A flytrap grown in strong sun develops colored traps and a compact habit; a shaded one grows floppy and green, and slowly weakens.
Water: Tray of standing water (about an inch) through the growing season. Rain, distilled, or RO water only.
Soil: 1:1 peat and perlite. No fertilizer, ever.
Feeding: It will feed itself outdoors. If you must feed one, use a live insect about a third the size of the trap. Each leaf only closes a few times in its life — springing traps for fun costs the plant real energy.
Winter dormancy: Required. From roughly Thanksgiving to Valentine's Day the plant shrinks to a small rosette and stops growing. Keep it outside, damp, and cold (it shrugs off Georgia freezes). Skipping dormancy kills flytraps by year two or three.
Flowering: Flytraps bloom in spring. Unless you want seed, cut the flower stalk when it appears — blooming is expensive and the plant grows noticeably better without it.