If you're looking to design on HoloLens, you'll have to rethink the way you do your design. As HoloLens designer Hae Jin Lee covered in her blog post, there's a whole world of difference between 2D and 3D design that needs to be taken into account if you're going to work on HoloLens.
Lee brought up 4 main points to teach designers a little bit about the HoloLens:
Good-bye frame. Hello spatial / diegetic UI
Lee made a point of talking about how diegetic UI is an important part of making truly immersive experiences in HoloLens. This form of UI is focused around making experiences lock on to one place in the user's world, instead of following them around in their display.
The return of skeuomorphism and magical interaction
Skeumorphism was brought back with the dawn of VR and AR, purely as a result of the realism that the medium demands. Having UI elements resemble their real world counterparts is something that just makes sense in the world of VR, and Lee embraces its return to popularity.
Understand different input methods
Lee talks a bit about the importance of the different input methods with the HoloLens, and just when it's appropriate to use each of the methods. Some of these methods are more laborious than others, so it's important to know what you're asking your user to do, and with what frequency. She also talks a bit about different peripherals that can be used with the HoloLens, opening up several new possibilities for the platform.
Sketch the scene and test in the headset
Planning out your work? You're going to need to sketch out your entire scene, not just a frame or two. Lee talks about what you need to do in order to effectively put together a scene in 3D. The requirements here are completely different than what you're used to in a 2D scene, so these tips are pretty vital.