Coriander (cilantro): A very short-lived annual, sometimes living out its entire life-cycle in a matter of 2-3 weeks. Those leaves won't have a good flavour (once they start changing to lacy, they've bolted), so just let the plants go to seed and die a natural death. It's too late to do much else! Those seeds will grow into more plants. Most people grow coriander by sowing new seeds every couple of weeks to keep up supplies of useful leaves. (successive planting)

Chives: only 2 inches tall?? They won't be seeds on the leaves, they'll be dirt or bugs (probably aphids). You'll get seeds after the flowers die off - and flowers haven't happened yet, have they? They'll appear on the top of long, firm stems. Chives grow in a clump which you can divide once the clump gets larger (say when it's about 30cm/12" in diameter). Leave them be for now, and never prune the leaves at all unless you're actually harvesting. Wait until you have enough leaves to use.

Dill: a photo would be useful. Dill can get about a metre tall, so it's still a tiny baby. Here's a picture of mature dill.

http://julielepage.com/blog/photos/2005/07/15/3.jpg

You can harvest the leaves any time you like, but never more than one-third of total growth at any one time, then let it regenerate before you harvest again. Same with most plants.

Basil: still a tiny baby. I'm surprised there are no flowers yet. Basil can flower from a very early stage, and it's from the flowers that you get the seeds (same with most plants). It has a LOT of growing to do, (it will get to about 1 metre tall, maybe a bit more, and about the same wide), but you can harvest the leaves at any time, taking no more than one-third of total growth at any one time. To encourage a bushier plant, chop off the flowers. If your plant ends up like mine, you'll spend a lot of your life chopping off the flowers!!

In brief, be patient!! Your plants are only tiny babies just yet, so you won't get any useful quantities from them. Forget about pruning for now. Wait another few weeks.

Meantime, do some browsing via the Search button here on this forum for more information.

You know, I really hate it when people try to generalise about 'herbs'. With 20000 known herbs on the planet, you can't generalise at all!

Fertilzer may be needed. Not those chemical ones, but something thats naturally based. Dill here, grows to 5 foot tall outside. Once the flower/seed heads form, the fern like leaves will turn a light tan color. Cilantro, as noted, has gone to seed. You pick that when the leaves are broad and look a bit like parsley. Once they slim down and seed heads form, they cannot be harvested as cilantro anymore, although the thinner fern like leaves do have some flavor. The mature seeds (actually tiny fruits) of cilantro are now coriander. Cilantro, once gone to see, will sprout those seeds next year. Using the poor quality 'Chia' seeds are not a good choice for decent herbs. You would be better off buying herb seeds specifically bred to be slow bolting and offer more fern type leaves. 3 weeks is not a long waiting time. Here, I start dill seeds right now, in the garden, and by the end of JUne they are nearly ready for harvest, and are producing when pickling cucumbers are also ripening. Basil also takes several months to give any amount of leaves to harvest.

Daisy - like you I first assumed that the OP meant that the coriander had bolted already. But when s/he says the chives also have seeds attached I think s/he means that the seed from which the seedling has grown is still attached to the baby plant. If this is the case then they are all fine. General advice would be to give them plenty of light, but not necessarily direct sunshine, fresh air, not too much water and little or no fertiliser until they are a bit bigger. All but the chives will be made bushier by pinching out the growing shoots occasionally but not until they have a few true leaves.

As you say it is not possible to generalise about herbs. It's just a label for a diverse number of plants which are used by humans.

I grow a wild onion, and these thrive in winter instead of the heat of summer. By mid August, hey have sent up a stalk that has a ball of tiny bulbils that I crumble and replant nearby he main patch. By the end of September they are sprouting and grow all through winter. I can go out even now and cut many of these to sue like chives. The bulbs in the soil are tiny pea sized and, usually produce for two years, then die oiut to be replaced by the new ones. Some of these are about 1/8 inch in diameter or slghtly bigger around. They do not produce seeds, but instead that small marble sized ball is the seeds which are tiny onions. Next to them, I grow garlic chive, which flower and do set black seeds in fall, that I replant.