You have much more leeway for tabletops - pretty bowls and pots, decorative watering cans, vintage punch bowls (it's fun to watch the roots grow through the sides of the bowl). Choose a container about eight inches deep and wide enough to hold all your plants with a few inches in between. Make sure there are drainage holes - if there aren't, drill some.
You want something that has good water retentive properties and is pre-fortified with nutrients. These plants won't have the benefit of nature, so all their nourishment will come from you.
While you're shopping for supplies, pick up a good herb compost (add into soil) and fertilizer, too. Fertilizing every couple of months or so will help make up for the nutrients your plants are missing by being in "captivity".
Think about where you'll be keeping the mini garden - most herbs love bright sunlight, but others prefer partial shade. It's important that all the plants in the container have the same light and water requirements.
You can start with seeds, but then you run the risk of having a few non-starters, which leads to wasted space in the pot. It's best to start with small seedlings about three to four inches high.
When you shop, look for plants that look strong and healthy with bright color and good, upright posture. Avoid plants that are already wilted or discolored. Go to a nursery instead of a big box or home improvement store - you'll find better-looking plants.
Check the moisture daily - plunge your fingers into the soil up to the second knuckle and add water if it feels dry. Don't over water, because potted plants run the risk of root rot. Snip off any flowers that start to grow, because you want the plant to put all of its resources toward producing more of those delicious leaves.