I don't bother if they make eye contact or not.
As long as they are listening to me.
I think trying to listen, take in what you are saying, respond to you AND make eye contact is sometimes too much for them.
Eye contact is more for us than it is for them.
Work on their understanding and their responses. Don't worry so much about the eye contact.
Before I realised that it was something that really we work on for us, not for them, I did do things like blow bubbles, let go of a blown up balloon, send a car down a little ramp, etc etc. I'd have whichever ready to go, make a sort of drawing-in-breath gasping noise, and when they made eye contact, let it go/blow/whatever. So they learned that making eye contact got the bubble/balloon/car/whatever.
I don't never ask for eye contact these days. Sometimes I ask them to look at my eyes and say "What do my eyes say?" "My eyes say I Love You." Sometimes if they are blanking me I will get their attention by insisting they "look at my eyes".
I don't think they make that much eye contact - ds1 does much much more than ds2 - but they talk now, they respond, they take in information, they do fine, it's not really a problem.
In fact. I am working on following instructions atm. Started with simple ones and getting more complicated. Last night I said to ds1 "Go to my bedroom. Stand at bookcase. Get the book that is on the highest shelf. The last book on the right hand side."
Ok, he went up, came back down with my inhalors but I repeated the instruction and he came back down with the book Bloody amazing!
He didn't look at me once.
Who frigging CARES!!!!
I cannot stress enough that it really doesn't matter. The eye contact I mean. Work on the other stuff.