Getting to Makena is easy--just follow the road signs from the Piilani Hwy. going south, keep driving along the coast, and you can't miss it. To get to Little Beach is a bit trickier; after you park your car and follow the path to Big Beach, catch your breath and take in the stunning view, follow the footprints toward the rock face you see at the end of the beach. Approaching the rock face, you will see a path that will take you up and over (or if you're seeking a physical challenge, might find the bouldering route). Really it's hard to get lost and you'll know you're there when you see a full moon ;). Certain stretches seem more popular with different groups, so I'll let you figure out the best place for you to sit, but it's literally all good.
PRO TIP: Go to Little Beach on a Sunday afternoon and evening for the drum circle and sunset. It's definitely a party so BYOB.
A taste of Sunday Funday on Little Beach: