I use the 1" bullseye stickers and it improved my accuracy a lot. It's like Mel Gibson said in The Patriot, "aim small, miss small."

As far as what standard, like Arthur said, shoot at a distance you are comfortable with. If you are confident you can hit the vitals at that distance, then make that your max. With practice that distance will increase. You should simulate real hunting situations when you make this decisions; clothing, stand height, broadheads, 3D target, etc...