A touch of orange paint on the front sight. Some folks like the laser sights for these little guns since the sights are so small. Some shooters also find that a grip sleeve helps get the trigger reach to be a bit better as well as giving a bit more purchase on the small grip.
Other than that, clean it lube it, load it and learn to shoot it. Get a good holster for it and enjoy.
Some can have some problems with metal peening of the barrel hood and slide, where they mate up. If you notice this problem developing contact Ruger and they will usually fix it.