Flowers are pretty easy to care for! Make sure you have planted the seeds in moist soil. After, make sure that they good a good amount of sunlight and water! About 1 inch of water per week; however, it varies depending on the type of flower and amount of rain in your area. The soil surrounding them should be moist, but not overly wet. Also, make sure the weed other plants that might be intruding on the space of the flowers.
It is important to also consider the height of the flowers and how tall they might end up growing. Considering this will help to make sure that specific flowers do not take up too much space.
If you are interested in learning more, I reccomend checking out this website: Visit How to Garden: The Basics