These guns are pretty good straight from the factory. However, if you find that you do not like the sights (some do and some don't) then check out some of the posts in the "gunsmithing" section about replacing them with the Wilson Combat three dot set. I did and I am very happy with the results.
I would start out by shooting basic WWB solid point ammo, then after you feel comfortable with the gun, start shooting some defence rounds and see which ones the gun shoots best. My PT145 does very well with Speer Gold Dot for short barrels.
BTW, welcome to the forum. Are you the same fellow that recently posted over at the firingline, or the high road (can't remember which it was...)?
Todd