Basil is beautiful, and possibly the world's most luscious herb. Most other herbs need to be used with discretion. But not basil. Basil is best if you use lots!
Like just about every other food stuff, basil tastes best picked fresh from the garden. If you grow your own, you can choose from the many different basils that you'll never find in the supermarket. Not just purple leafed basil, or giant lettuce leafed basil, but ruffled basil - wonderful crisp green leaves, perfect to mix in with a chicken salad, or lemon scented basil, aniseed basil, cinnamon basil, intensely fragrant small leafed basil, mild perennial Sacred basil that goes so well in Thai, Vietnamese or Laotian dishes, or perennial Greek basil. (Heavy frosts will kill both Sacred and Greek basil, so they are best grown as annuals in frosty areas.)
So how do you grow this wonderful stuff? Buy a packet of seeds, or even easier, buy a punnet of seedlings. Basil seed is tiny and can take several weeks to germinate, so if you grow your basil from seeds, the weeds may grow before the basil does.
Plant it in a sunny spot, though basil will tolerate light shade too, especially in hot climates. From Sydney south, try to make sure that your basil has at least four hours on sunlight a day.
Basil grows best in very fertile soil - the more feeding, the bigger the leaves. Unlike many plants where overfeeding produces insipid plants, underfed basil is less fragrant than a well fed plant. Give your basil frequent doses of liquid manure throughout the growing season to keep up leaf production. The more you pick your basil the more you need to feed it.
But most important: PICK YOUR BASIL OFTEN! Plants that don't get picked turn leggy and go to seed too soon. And always pick off the flower heads before the flowers bloom- and definitely before they set seed. Otherwise your poor basil plants will put all their energy into growing seeds, not big fragrant leaves for you to eat.
In tropical areas, keep picking off basil seed heads and your plants will grow and leaf for several years. In cool, cold or temperate areas, say goodbye to your basil at the first frost - so make sure you eat lots before that happens.