My experience is by "raising" the height of the shield I'm looking at the top part of the shield and where it sits when I'm riding.
Depending on the mounting kit and how it is adjusted it will sit higher if you have the shield upright, say a 90 degree angle. Getting it lower you would adjust the rake. For example a 45 degree angle would "drop" the top of the shield lower.
Now if you're thinking of wanting the shield to be higher, you might need to get a shield that is physically bigger or taller. Like Blackie mentioned, this would depend on the model or style of the shield. For example the Hellcat and the Big Top. Both Memphis Shades but both shield differ in size.