Don't upgrade just spam would be the best piece of advice i could give. Also the opening hint is a very very good one.

I think Shooting technique differs depending on factors like the type of weapon used (from a handgun to a sniper rifle), the distance to and nature of the target, the required precision and the available time. The prone position, the kneeling position and the standing position offer different amounts of support for the shooter.When i was in college  I often participated in shooting competitions.Holding the gun sideways, as is sometimes seen in movies and on television, is not recommended because it makes the gun almost impossible to aim.