To take advantage of the high data transfer of laser communications, a spacecraft will have to aim its laser at a receiver on Earth with extreme accuracy. It's hard but not impossible, and OPALS is going to prove just that.
The OPALS team is on track to launch their flight hardware to the ISS on one of SpaceX's Falcon 9 rockets next July. Once installed, it will demonstrate one way communications (from space to Earth) every time the station passes over the telescope at Wrightwood, about once every 2 or 3 days.
The team will keep a close eye on the ISS, tracking its passes over Wrightwood by calculations instead of a tracking system. Just before an overhead pass, the telescope will look to where the team predicts the ISS will be. Once the station comes into view (the telescope is surrounded by trees) the flight system will detect a beacon on the ground then use its gimbals to get into a position where it's looking down to the telescope. Then the laser will fire, transferring a preselected loop of video data for the duration of a the 100 second pass.