With my daughter, I always use the word "look" for the eye contact. If your child does not respond with it, hold the childs face on his both cheeck facing him and say "look", once she did look at you even for just a second, say "good looking". Start with the childs name, look and whatever the command is, example... ella, look, command. Pointing at the object can also help her understand what the command is, with my daughter I "introduce" things to her, I always ask her "what is this?" if she does not respond then I tell her what the thing is called. Then I ask again until she understand and remember.
To a non-verbal child it is not easy or even impossible to explain why things are like this or like that, but this does not mean if your child is verbal it will be different, maybe easier in some point. Since my daughter is considered non-verbal (although she is trying to express herself on her own way) we, always make a point to talk to her and explain why we cannot buy certain things she wanted, in shortest sentence we can possibly do...
asking for things for boys or men... "for kuya not for ella"
"for daddy not for ella"
asking for very expensive toy.... "no money"
asking to go to a mall..... I schedule when we are going. then I ask her "ok?" but if you promised you will go on that date just make sure you will.
asking for junk food.... eat rice and chicken then chips
The key to this is be creative, and learn how to cope with your child, your child is not the one who will adjust for you, you and your family should understand his moves, his weakness, his tantrums. He will not tell you what he wants so we as parents should know even without the words.