By giving it an 80L tank with good filtration, no sharp-edged decorations, letting the tank cycle, testing the water regularly (pH, ammonia, nitrite and nitrate), changing 50% of the water every week, never cleaning the filters under tap water.
Feed it a good, varied diet, since you chose a pearl scale, which will be devastated if you'd just feed it flakes because of the compressed organs inside the little round body. Be sure to give it a good quality staple pellet and fresh vegetables such as shelled peas, blanched lettuce, spinach... plus live foods, blood worms, tubifex, shrimp, freeze-dried, frozen or fresh. (More info on that here: (Link is not visible to guests. Please register to view.) )

Optional, provide a natural and comfortable environment for the fish, with a nice, smooth gravel, a few round pebbles and some plants such as Java Fern, Anubias (of various kinds and sizes) and some Elodea. It will probably eat the elodea though, but it's a nice snack!

One thing I know about pearlscales is that if a round pearlish-looking scale on the body of the fish has come off, it will not grow back the way it once was, but will be replaced by a normal scale. This means you should try to avoid rough decorations that the fish will scrape against as well! 

Love to see pics if you get the chance to take some