I did not co sleep, but we had a pac n play in our room and had to transition from the pac n plany in our room to her crib in her room.
Here are a few suggestions, first you could try something like a pac n play in your room for awhile so he is still in the room but right by your bed instead of in your bed. I used to take my shirt off right before bed and would put it in the crib flat where she would be sleeping and tuck it around the mattress so it will not bunch up, but it had my scent on it and she slept better.
I would then put him in his crib awake and let him play some in it to get used to it. I also started my child off by taking naps only in the crib because it was for just a short time. I then moved the pac n play into her room until she got used to sleeping out of our room then transitioned her into her bed. It took awhile, but she transitioned pretty good without a huge amount of crying.
If you are wanting a book, "Good Night, Sleep Tight" by Kim West really.......... helped me because my child does not sleep well. It is a more gentle version to just crying it out. What ever you decide to try, you need to be consistent or it might not work. Good luck.