depends entirely on which country u live in..how bigu want ur ngo o be..its growth,spread and network..firstly,u need to construct an action plan,choose what kinda work ur ngo should do,what kinda people would it xater to,financing,sponsorship,funding ideas need to be gathered.u need to chalk out the objectives etc.n then register the ngo.u need to consult and contact the registering authorities in this regard..setting up an ngo is a novel idea but requires a very professional approach.u need a workforce,managerial expertise etc..but u have to start from a grass root level.u might even choose to be a part of an umbrella organisation which might supprt u with financial aid and provide expertise in running the ngo.u can contact UNICEF,CRY ETC.