The poster above is 100 percent correct about hustling the whole time.  I would also suggest to show that you are a team oriented player.  Cheer the other guys on during conditioning drills.  It seems kind of silly but be first to high five someone after they did something good.  Being able to bring a positive energy to a team is a very important quality that not many people have.  If you can do that, you shouldn't have any problem being noticed!