Fortunately, "Lazy" is Mother Necessity's husband (sorry boys, you get to be "lazy" because the woman in the relationship was already named. This is not a comment on my husband, he is probably a lot less lazy than I am). Therefore, I just put the piece of the pattern that makes the side over the already finished edge where the buttons are. There is a handy x that ends up marking where the start of the place where the buttons will be on the pattern, so I just lined that up with my already existing edge when I cut. I cut both sides out from the side with the buttons on it so I could make my own button holes where I wanted them to be. You just have to make sure to cut one side out with the pattern flipped over. I used the buttons from the shirt.
I also cut out longer sleeves. I cut them from an edge of the shirt, so they were already hemmed. I roll them up to make it look like there is a cuff. The last change I made is I made the pleat in the back go the opposite way from the plea Jessica made. That is the way Patrick's dress shirts are made. You can do that by just making what she made backwards.
The tie is just a ribbon. This ribbon is 1 3/8 inches thick and about 32 inches long from tip to tip. You can adjust as you think is best. Both ends are cut into a point, like a tie. We just tied a tie (here is a youtube video of that, it you need it) with the ribbon. To keep David from choking himself if he pulled on it, we pinned it with a safety pin through both sides ends and part of the knot. This made it much like the collar. I suppose you could also hot glue inside the knot and cut off the loop part, keeping it always tied. Then, you can glue it to a hair clip or paper clip.
Another note: This ended up getting very drooled on. I used some ribbed ribbon because it was what I had on hand, but it was probably better than the satin ribbon because it wasn't water-spotted. If your baby doesn't drool, it might not matter. However, if that is the case, please tell me what you do to get your baby's saliva to stay in his mouth.