What are these plants?
I believe the first plant pictured is in the Peperomia family. That plant does well in low light and likes to be kept on the dry side. Below is a link to information about Peperomia. Scroll down the page and you'll see a picture that looks like your plant.
The second pictured plant is possibly in the Echeveria family. These are difficult to identify because there are so many of them. However, the care for all of them is essentially the same. Be sure the pot drains well. Use part sand in your potting mix and water infrequently making sure that the soil dries out between waterings. Also be sure your plant is getting a good amount of light and warm temperatures. Most garden centers carry succulent potting mix.