Basically as was said below, just write applications for desktop. Some caveats I've found though, is to minimize the horizontal of your app (to even just a couple hundred pixels wide), and verify that treating your mouse as touch input works (such as scrolling) and testing like that.
When pretending your app is running on a pinephone works properly-ish, I'd call it good. Any functional client or service is a boon to mobile Linux; and even if it's imperfect, so is everything else for now :)
