Well most of the time you have to find your way to make and extract in order to make it more effective, but for this you would need some kind of freeze dryer or atomizer. the process is actually simple, you would have to make some kind of infusion like a tea and then put this on the machine and evaporate all water and whatever is left is considered an extract (this get to be expensive becuase you will need this machine). Another method is to make a hydro-alcoholic extract in which you used alcohol to retrieve the active ingredients from the plant into an infusion but is more complicated that the previous one and need some kind of technique. I guess you best option is just to make and infusion with the part of plant that is supposed to be rich in active ingredients (root, petals, trunk, bark, etc) and just drink it like tea. Just try to do some research about at which temperature those ingredients will loose their strenght or things like that. Then you will be able to make an infusion that will actually work.