For Android implementations, if you pay attention to the Material Design guidelines, even if you don't have a good designer on the team, it probably won't suck. It might be pedestrian and form-oriented, with less direct manipulation than it should. But it won't look awful.
This. For design-challenged people like me those guidelines are lifesavers. Ironically, I'm not a big fan of Material personally but it helps a lot to have these kind of guidelines handed down to me.
