how to find a reputable licensing agent

i have an invention for an improvement on an exsisting product i have just sent in my proisional patent application. The problem i have is i am a horrible sales person for one and i dont have any contacts as this is my first time trying to monetize an idea that i came up with. So my question would be how can i know if a licensing agent is legit is there a list anywhere that reviews licensing agents and can maybe catagorize them into various feilds of exprtise. Any help or guidance would be GREATLY appreciated.