My main goal was to figure out what he wanted so we started with request items like milk, cereal, chicken nuggets, poptarts, apples, popsicles, movie, etc. We took pictures of some and developed them as wallet size. For other stuff like poptarts, it is easiest to just cut out the picture on the front of the box. We started out by kind of playing dumb - we knew what grunt he used for milk but acted confused and grabbed 2 pictures and asked 'do you want milk or apples' then helped him grab the picture and made a big deal about giving it to him.

We started with pictures of food that my son would pick between.. "Do you want milk or juice?" Our Speech Therapist had black/white pec cards but he wasn't that interested. I decided to make a set specific to the exact foods that my son ate and it helped. I have a laminating machine and I bought a package of business card blanks from the local office store. With our camera I took specific picitures of his favorite juice cup, a dish with goldfish, a mini box of raisins, yogurt, etc.. And then just printed colored pictures small enough to fit on the card and then laminated it.
The size was a workable one for him and the lamination made the cards sturdy.
Once we "worked" with the ones that I personalized him he really flurished. He was more attentive by far using the pec cards I made.

when my son was young we used sign language (very basic stuff) and picture communication...it all helps. I had a great step by step picture board i made for him on the steps of using the potty :) it worked great. Our therapist told us to ask him to look at me too when we communicated. even if that ment i had to keep on repeating "Mikey please look at me" and move his face to face mine. He finally started to talk at almost 4yrs old. To this day sometimes when my son talks he will use sign language with his hands to communicate yes or no or open...and he is 10 now and wont stop talking now ;) he also is in gifted classes at his school. Amazing how different he is now from then. Keep it up and you will see wonderful results

The pec cards my therapist started for my non-verbal son at 2 were all things he liked or enjoyed doing...like "bubbles", "swing", "balloon" and then she'd throw in a random thing like a spoon. But when he pointed to the right card, he was rewarded with the activity....bubbles, swinging in the blanket, blowing up a balloon.... It just reinforces their use.
I say that, but it never stuck with my son. He still goes and gets the bubble bottle and brings it to me....or me to it. lol But, in theory, it SHOULD work! =)

It's all about functional language. So start with items he needs to request. Then the program should move for there. Pyramid provides training for PECS. I would make sure everyone working with him (and the parents) go to the basic training.