If you haven't started seeds yet, read this post:
Water them...every day. Seedlings are fragile. They need to be watered daily, at least at my house they do. We use wood heat and the air is dry. I also find that the cardboard containers seem to dry up much more quickly than their plastic counterparts. I use my dish soap container (after being well rinsed) to water my little babies. I try in general, to miss the leaves. and water at the base of the plant. In addition to watering, at this point, you will want to remove any extra seedlings. I keep one per pot. I generally remove the weaker looking specimen - in the picture above the choice is pretty obvious. The reason for doing this is to keep them from competing for resources, so in this case, the runt goes. For some reason, I really seem to struggle when they both seem pretty healthy. I guess I feel like I have nurtured these little lovelies into being and it is hard to just rip them up and throw them out - a bit silly, I guess, they are plants. You also will want to turn your grow light - remember that I use a simple florescent light and it seems to do the trick just fine - on every morning and then turn it off again at night to replicate the day light that your seedlings would have if they were outside.
The other responsibility you have at this point as a plant parent is to re-pot the seedlings as they get too big for their containers. I will post on this once my seedlings are ready.
It would be prudent to share why this is necessary: I want my little babies to thrive and they need room to stretch their roots in order to grow. They run through all the water, nutrients in the soil, etc. too quickly for me to keep up with them in these tiny spaces and they can't get bigger when their growth is thwarted by the size of the container.
Today, I decided to give them an extra special treat and I am feeding them some Seaweed Concentrate - I hope they like it.
Almost time to transplant - I will post on that as soon as the need arises. Until then, happy gardening.