how to set the parameters of OMPL for better planning

Hi,Guys! I use OMPL to plan a trajectory in MoveIt! There are several algorithms in OMPL such as RRTConnect, PRM. Using default config in the ompl_planning.yaml, the trajectory seems not that well. It is not the optimal one and has a lot to improve. I wonder how to set the parameters of OMPL for better planning in MoveIt!. I found some tutorials like [ompl_ros_interface](http://wiki.ros.org/ompl_ros_interface), but it was for groovy and obviously out of dated. Is there any tutorials for indigo? Can I modify the script in OMPL for better plannning or can I write a planner using RRT or PRM and load in MoveIt? Looking forward to your help! Thanks!