Their names matter very little, (except that "Percival" needs explaining because it's so odd) . The plot matters a lot. Writing without a plot in mind is like driving with no destination in mind -- you don't know where you're going or if you've arrived, so you just keep going until you run out of gas.
So before you start writing, have a plot in mind. It doesn't have to be elaborate, but it must be complete, from start to finish, even if it's only five lines. You can improvise within that framework, but you must know two critical things: the conflict and the resolution of that conflict.