Select your flowers. Pick ones that are fresh, and keep the combination simple: monochromatic, shades of the same color, or up to three complementary colors.
Remove unwanted/wilted bits. Make a diagonal cut near the bottom of the stems (cut to size depending on size of vase if needed). Remove any foliage that will fall below the water line in the vase.
Clean vase if needed. Fill half to three quarters of the way with room temperature/lukewarm water with floral food. Create a guide grid using floral tape or wire if desired.
Add flowers. First, any base greenery, then focal points/larger flowers, then filler flowers/smaller ones, then “floaters”/miscellaneous filler pieces. You can use a Lazy Susan to rotate the vase and see it from all sides, or turn it yourself.
Give the flowers a light spritz of water to recreate the look of fresh dew.