Also don't use the plastic tube the hydrometer came in. It can stick to the side and give you a false reading. Buy a hydrometer flask. They are cheap enough and have a base so it will stand up by itself.
Your reading should also be at 60°F for most hydrometers but will have a conversion chart for other temps. The difference is not much though. For FG I just figure if it's around 1.010 then close enough. Some beers, like your Stouts, with a lot of un-fermentable grains may finish higher.