This forum is not for tutorials ! read the rules before posting something, you have a lot of tutorials on youtube, google and other websites so try to understand, because is not the first time when we see you don't want to understand.
I don't think this is wrong. I came here to learn with a learning attitude. The forum is used to ask questions, my question classification is correct and the question makes sense. if ask a question is not free, this is actually a retrogression of human civilization and it is really a very very primitive behavior.
I wouldn't exactly call that realistic. Please just do a search for tutorials in your favourite search engine. It's not something a lot of people will even try, so I wouldn't expect too many results at all.
As for your other question: "rendering the skin"
Which skin? People? naked cats? zebras?
And what exactly is your issue with it? Drawing at all? being realistic? the lights and shadows? the structure?
Please put in some effort, because you will need to put in even more effort when actually drawing it.