Before you start planting a garden make sure you have well prepared the soil. By this I mean have you loosened the soil by hand or with a tiller to allow for the aeration? Have you softened your soil with fertilizers and new topsoil? Most gardens should be lightly tilled in the spring before planting to kill weeds and smooth the soil. Correctly tilling the soil will enhance the absorption of water. Remember also that nitrogen is an important critical nutrient to plant growth so give it time to settle into the soil. Too much nitrogen will make for more vines that fruit on plants such as tomatoes or potatoes. Once you have readied the soil, its time to begin planting.
Since you have had all winter to lay out your design and spring has nearly arrived, digging and planting are close at hand. Let's say that we are novice gardeners and are planting for the first time, have a relatively large space and don't know a petunia from a begonia, or an annual from a perennial. First thing an annual (you must plant every year, but they bloom almost all summer) and a perennial (comes back year after year, but has a shorter booming span). Then pick your plants, and try and pick plants that are well suited to your climate and soil region. Know how much sunlight you will be getting in the spot that you have picked out. Annuals such as marigolds, zinnias and impatiens are fairly easy to grow.
If you live in a region where late frost is common, don't plant anything until this danger has passed. A simple solution is to start your seedling plants indoors from seed using containers or flats that are designed for indoor planting and the use of a sunny windowsill or an artificial growing light will work wonders. Always make sure your seedlings are kept moist but not wet, never allowing them to dry out. Water every other day or so while they are small then cut back as they grow bigger. If you start with seeds indoors simply follow the packet instructions and when the weather is right transplant outside to fresh air and sunshine.
After plants have been transplanted outside continue to water every other day and add mulch around them (when they are large enough) this will cut down on weeds and hold in the moisture from watering. Keep the weeds pulled before they get to big (by hand is best) and if you fertilize with a liquid, fertilize every other month and if with a dry fertilizer use again about half way through the growing season. Always if possible water in the morning when there is less evaporation from the heat of the day. Below is a list of some of my spring, summer and fall favorites.
Snapdragons - Beautiful array of colors from early summer until late fall
Daylilies - wide varieties, blooms only last a few days but hybrids bloom all summer
Marigolds- easy to grow and come in a variety of shades, bloom summer through fall
Impatiens- tiny cute flowering plant, but doesn't like very hot weather
Pansies- beautiful in all sorts of colors, grows better in cooler weather, velvet feel with black centers
Rose Moss- does well in hot climates, an array of colors and an excellent ground cover
Begonias- beautiful, but sensitive, not heat tolerant
Forsythia- beautiful flowering yellow bush that lets you know that spring has arrived
Petunia - an array of colors, heat tolerant and easy to grow, just right for a novice
Nicotiana - Multiplies and comes back years after year, has a smell that will attract Hummingbirds for miles white, yellow or purple
Gladiola - a garden favorite in mid and late summer
Crape Myrtle - beautiful pink flowering bush which is a late spring early summer favorite
The pride of my own garden;
Bougainvilleas, - climbing woody ornamental plant with red, purple or pink leaves and tiny white flowers
Camellias - glossy evergreen leaves with rose shaped flowers
Rose - every color, every smell, the very sight is sheer joy
Eudora DeWynter offers tips on How to Plant A Garden on her blog at http://www.gardentoolguru.com