Mare Fecunditatis, the Sea of Fertility, and Mare Nectaris, the Sea of Nectar, are the dark lava plains that dominate the south-eastern quadrant of the Moon.
They are easy to see in binoculars. While the Moon is still a fine crescent, use your telescope to look for the large and easy to spot craters of Langrenus, Vendelinus and Petavius.
More and more impact sites will come into view as the lunar phase grows and the crater-strewn southern region of the Moon becomes visible.
Update! For an alternative, inverted view, here is a chart with south at the top.
You can download a check sheet for the entire list of 50 features here! (PDF file).