As with all plants, some flowers are harder to grow than others. For your first attempt at planting flower seeds, start with varieties that are easy to grow, such as cosmos, nasturtiums, sweet peas, a wildflower mix or sunflower seeds. Wait until after the last frost in your location, before getting started on working the soil for your flower beds. The National Climate Data Center has information on determining the final freeze date for specific locations.
Remove all weeds and other debris from the flower bed area.
Dig up the soil with a pick or shovel and mix in compost. It will amend a sandy soil to hold more water and a clay soil to allow for better drainage. It also adds nutrients. After the compost has been worked into the soil, rake the area to even it out.
Dampen the soil by spraying it with water. Do not create sopping puddles.
Read the packet directions for the flower seeds you have chosen. It will inform you on how deep and how far apart to plant the seeds. Generally, the larger the seed, the deeper it is planted. After poking your seeds into the soft, moist soil, cover the hole with soil. Very fine seeds are merely pressed into the top of the soil with no cover.
Water the garden the next day with a very fine water spray, so that the seeds won't be dislodged. Keep the soil moist until the seed germinates. Soon the seedlings will grow into mature plants that will flower.