Consider the herbs you want to plant. Think about their types. Would you like annuals, biennials or perennials?
How much space will they occupy in your garden? If you want, you can purchase a book that can give you the right information on what specific plants you are planning to grow.
List or draw your garden on paper first. Separate the annuals from the perennials so when the time comes that you have to pull out the annuals, you won't be disturbing the perennials. Perennials can be planted on the edge of your garden so when it is time to till your garden they won't be in danger of getting dug up.
Another thing to remember is that you have to plant the tall ones at the back and the shorter ones in front. Also, provide your plants with enough space to grow. Proper position shall help you in this area.
If you would rather keep herbs out of your garden (and some are quite invasive) you could have herb pots. These are large containers with three or more outlets for the herbs. Fill the pot up to the first outlet and plant it before continuing on with the filling and planting process. Usually, the herb that requires the most water is planted in the bottom hole, while the variety that requires the least, goes in the highest hole.
Some Design Ideas
You can consider having a square herb bed. You can have your square bed divided into four by two paths crossing at mid point measuring 3 feet. You can border it with stone or brick. A wooden ladder may also do the trick. You can lay it down on your garden and plant your herbs between its rungs. You can also choose to have a wagon wheel bed. Planting here is like planting with the wooden ladders. Plant your herbs in between the wagon wheel's wedges.
Get Your Plants Growing
Of course, different plants have different needs, but many of them require alkaline soil. This is the reason why you have to determine the herbs you want to plant in the planning stage. This can more or less help you find out how you should care for your plants. If you germinate your herbs from seeds, remember to follow the directions on the packet for soil, watering and temperature.
Herbs are some of the easiest plants to grow. You just have to provide them with an effective drainage, sunlight, enough humidity or moisture and fertile soil. Even with just minimally meeting these requirements they will be bound produce a good harvest.