How to be more realistic?

[Milena Mantovani Buzzinaro]

hey guys, my first post on this site! I may be doing stupid things, do not know right post kkk but finally I did this illustration and would like some tips, some advice and such to my painting becomes more realistic!
I'm not knowing how to ask for help, tell me, why in addition to being new digital painting, I am new in this forums and through digital!
I hope to help you because I have a critical look and it is us!
Thanks for watching!