First of all, the most important aspect of designing the herb garden is to assess the available place or site. You should also check that how much time that site remains under direct sun light.
You should know that herb garden requires direct sunlight and you should select a space that gets sun light for at least 8-10 hours. It will help in the desired growth of herb garden.
You need to decide the purpose of designing the herb garden in your home because it will help you to select the specific type of herbs. Decide whether you want to grow culinary herbs or a medicinal garden because these different types of herbs require different environment for growing well.
Another important thing is that you should know that which herbs are suitable for the soil and climate of the site where you want to grow the herb garden. You can take help by the nursery staff in your area as it will help you in making the right selection of herbs for your herb garden.
You should also become a member of local garden club which will help you to get acquaintance of many people having herb gardens. You can also take guidance from these people who will let you know how to design the herb garden perfectly.
Becoming a member of local herb society will also help you in getting information about herb garden. You will learn many things by attending the meetings of local herb society which will be beneficial for designing a desired herb garden.
You need to enclose your herb garden by building a wall or fence around it which will provide it protection from the animals etc.
You should also add a small water fountain in your herb garden which will attract beautiful birds and will give a fascinating touch to your herb garden.