Probably lots of different ways to do this.
1. Have him working for a toy, put toy in armpit, they look at the toy, when he's in position, mark & give toy.
2. Some people spit treats, seriously, keep them in their mouth, and spit treats, dog learns to watch your mouth (this is too gross for me, I might just finished picking up poop, so not gonna put hotdog bits in my mouth).
3. Teach watch, or look at me command, ie, attention as a separate command.
try kikopups youtube channel for this sort of things, basic attention, basic obedience if you are into motivational training (using treats); I ignore her preachy lectures, but she provides a good refresher on how to motivate dogs to do things for you, including sit front.
4. In the beginning, call your dog, but reward by throwing treat or toy between your legs, dog learns to run right at you. Then when you keep your legs closed, will run up straight and front (I've used this to clean things up and amp things up).
Attention, looking at you, is a basic behaviour you want in most commands (at least heel work).
Oh, 5. If your dog is giving it to you anyway most of the time (and if you're using treats and toys, they usually do) just make sure you don't reward, mark & treat, or toy without them 1st giving you eye contact.
I won't release my current guy from a down-stay until he makes eye contact (only works if they will freely give that most of the time)
That's a start.
enjoy rally-O fun for dogs and people.