You just approach them thats it, theres always a chance they reject you its unavoidable but there is also a chance they do not reject you and even if they did reject you with every error you learn you continuously improve your habits and skills and from each attempt it will be better and so on and forth there is no reason to not approach them as you mentioned your a average looking guy, afterall You really need to be confident besides looks your behavior the way you act speak and talk is really important as body signs are somewhat a translator for your character so just try to be as Open and Confident as you can be and dont let your shit down because you failed once