1. You will need to first decide where your garden is going to be located. After you have selected the location of your garden, you will need to evaluate the soil. Before planting begins, you should put a lot of effort into making the soil healthy. The soil will contribute greatly to how your flowers will grow and how healthy they will become. You may want to purchase a soil testing kit at you local home and garden center. This test will help give you an indication of your soil's needs. If the soil is good and healthy, you should still add manure or compost to it. If the soil is clay, it will need to add compost, peat moss and sand to get it good and healthy. The soil should be able to hold some water, but not become water logged.
2. Next you will need to decide on the type of flowers you want to plant in your garden. Your choice of flowers should be determined by the environment in which they will be planted. You will want flowers that grow best in the type of climate you have and the type of soil. You should also take into consideration the amount of sunlight or lack of sunlight the flowers will receive. Research flowers that you would like to have in your garden, if they are not suitable, find out if there are flowers that are similar and if they would flourish and grow in your garden. The library, gardening websites, and your local home and garden center are great places to learn about the different types of flowers and growing recommendations. You can also receive tons of ideas, tips and suggestions.
3. Once you have decided what type of flower you want to plant in your garden but before buying them, you will need to draft a sketch of your garden. You will need to measure the garden area. Using graph paper, sketch the planned design of your garden, include the garden size and where in the garden you intend to plant flowers and the type of flower you intend to put in that spot. You may find it helpful to know the dimensions of the flower at maturity so you don't end up overcrowding flowers and not enough flowers will make your garden look stark and bare. This sketch will also help you to determine the amount of each type of flower you will need to purchase or how many seeds you will need. Take note of any other items that you will be needing for your garden such as shovels, spades, fertilizer, and so on. Also on the same piece of paper write down any questions you may have so you will not forget to ask someone at the home and garden center when you go to purchase the flowers and things that you need for your garden.
4. It is very important for your safety to call your local utility companies before you start to dig to make sure you don't run into any underground cables.

And don't forget to enjoy the flower garden you have created.