Tulips are the exception. They prefer their water straight. Color is tulips strong suit. You can create a wild riot of color or try more subtle single color combos such as purple with lavender, light yellow with deeper yellow. Flamed or multi-colored tulips look great mixed with solid color tulips in coordinated shades.
Tulips combine well with other flowers.
If combining tulips with daffodils, first tear the daffodils by trimming the stems and keeping them in a separate container of water for a few hours before adding them to your arrangement. This step allows the slimy alkaloid stuff in daffodils stems to run off. This sappy substance can adversely affect other flowers, shortening their vase life.