Tip #4, shoot at the lowest possible ISO
Shooting at a higher ISO will cause some digital noise in your image. The higher the ISO, the more noise you get. Some full frame cameras actually do quite well at compensating for that noise but it's still there. In a studio, especially if you're using artificial light, there's no reason not to shoot at the lowest ISO possible (unless you want the grain in your shot).
Your camera's lowest ISO will most likely be 100 when you take it out of the box. Some cameras have a lower setting (ISO 50) that you can enable in the menu.