In my view, the best way to ride upwind
is to use a keel or a proper fin. Not the little fins most kite board have, but something more like this ...
flysurfer-uk.com/product/flydoor-5/The FlyDoor has a small (detachable) fin (or I prefer a keel) in the middle of the board, to actually give you really good upwind control, just like a sail boat.
There are some other variations out there with even bigger keels, but the concept is the same, as per sailing.
Why is a keel important (and why foil kiters always go where ever they want - especially up wind)?
www.discoverboating.com/resources/article.aspx?id=251Everyone seems to talk bigger kite or a bigger board (both), and yeah they help, but really good upwind stability and control of direction, can only come when you command it by placing a keel down into the water. Without something like that, you're still skimming the surface - literally. Besides, a bigger board only acts as a keel more than a smaller board because you have more of the corner of the board in the water - hence it acts like a keel or rudder.
But meh, what do I know right?!