To maintain the beauty of your arrangement of mixed white flowers in a glass vase, follow these care tips:

1. **Fresh Cut**: Upon arrival, trim the stems of the flowers at an angle. This helps them absorb water more efficiently.

2. **Clean Vase**: Use a clean vase and fill it with lukewarm water. Make sure the vase is free from any debris or bacteria to prolong the flowers' lifespan.

3. **Water Level**: Keep the vase filled with enough water to cover the stems of the flowers. Check the water level daily and top it up as needed.

4. **Location**: Place the vase in a cool area away from direct sunlight and heat sources. This helps prevent the flowers from wilting prematurely.

5. **Changing Water**: Change the water in the vase every 2-3 days to prevent bacterial growth. Before adding fresh water, trim the stems again to ensure they can absorb water effectively.

6. **Remove Foliage**: Remove any foliage that falls below the waterline to prevent bacterial contamination and keep the water clean.

7. **Ethylene Sensitivity**: Keep the flowers away from ripening fruits, as they produce ethylene gas, which can cause the flowers to deteriorate more quickly.

8. **Enjoyment**: Finally, display your arrangement in a prominent location and enjoy the beauty of the mixed white flowers. Remove any wilted or spent blooms promptly to maintain the overall appearance of the arrangement.

Following these care instructions will help prolong the freshness and beauty of your arrangement of mixed white flowers, allowing you to enjoy them for as long as possible.