I have never done this before and it's still work in progress but I can tell little bit how I've started this with Hauru. I have no idea if I've gone about it correctly or not

So I too would appreciate any insight people might have.
First of all, in the beginning especially, I always controlled the skateboard, held it with foot or hand so that it couldn't do anything unexpected and scare/hurt the dog. I started shaping him to stand on the board and feeling comfortable with it, also I taught him to stand on the board while I rocked it back and forth a bit. Just to make sure he was comfortable with it, even though he isn't the type of dog who would be scared by something like this.
Than I began luring him to move the board himself, first just a little bit while he kept he's both back feet on the ground. I helped him at this point too by controlling the board, making sure it didn't move too fast and also giving him a bit of a kick start if he had trouble getting the board to move. I want him to skateboard with just one back paw on the ground so once he was getting the idea and could move the board quite easily I taught him to stand like that on the board without moving it. And than again introduced movement by helping him with my hand/leg. That's the basic form of this trick I think, but I've been trying to take it further a la bulldog Tillman and other skaters like him.
At the moment Hauru can skateboard pretty well on the street if he's just moving straight forward but he cannot steer the board (I'm not sure it's possible either, I think the skateboard I got him might be too rigid to respond to he's weight shifting) and he has begun jumping on the board with all four feet if the speed rises but he won't stay on it for long, I guess he is a bit unsure about it. Lately weather here has been quite bad and winter is coming so I doubt we'll be able to work on this much until next spring but my plan is to teach him to ride the board, just asking him to sit/stand on it like I did in the beginning and pushing him around for longer distances so he'd understand that he's absolutely right when he's thinking about jumping on the board in higher speeds. Maybe he'd also figure out the steering that way, I don't know.
Lot of this has been just taking things slowly, not getting frustrated and sort of letting Hauru figure things out for himself. My job is mostly to build the motivation for it and to keep him safe. Although he has begun doing he's own tricks, he slams he's feet on the nose of the board so that it flips over with a huge bang and other stuff like that so he certainly isn't that concerned about the board getting out of control

It's a lot of fun, I've been thinking of getting a better board for Hauru... I can just imagine the people in the sport store if I go asking them about suitable boards for my dog