It has been a long time since I have sewn clothes. But now I started back again. Next in line is a kid's cap with earflaps and baggy pants.
I didn't have time to make a tutorial for this post, so, sorry. But I will give you a link where you can find all needed info. If you don't know how to make a pattern in your child's size, I advise you to take another long sleeved t-shirt of your child and make a pattern from it.
I deliberately made the collar bigger than necessary, because little M doesn't like to put his big head thought small collars. ;)
Well, and a pocket. It looks good in black- and- white. The pocket won't be used to carry heavy things, at most a few candies. :)
Here you will find a tutorial about how to make a standard kid's long sleeved t- shirt.
And here how to make a collar.