The further you are in advance of your own positions, the more likely your artillery will shoot short. If your advance is going well, you are walking into an ambush. The quartermaster has only two sizes, too large and too small. The only thing more accurate than incoming enemy fire is incoming friendly fire. There is nothing more satisfying than having someone take a shot at you, and miss.
Professionals are predictable, it's the amateurs that are dangerous.
Don't be conspicuous. In the combat zone, it draws fire. Out of the combat zone, it draws sergeant. The only suppressive fire works is when it is used on abandoned positions. Never draw fire, it irritates everyone around you.