A lifting barrage was a development in which the barrage lifted periodically to a target further back, such as a second line of trenches. This was countered by the defenders infiltrating troops and machine guns into no-man's land or the areas between their own trench lines, so it was found necessary to comb the entire area of the advance with artillery fire. A creeping barrage (also called a walking barrage) was a barrage that lifted in small increments, perhaps 50 yards, so that it moved forward slowly, keeping pace with the infantry. A rolling barrage was more sophisticated still, with two or more curtains of fire, one behind the other, so that when the batteries firing the rearmost pattern ceased fire to lift the barrage, there was no pause or gap in the barrage. Those batteries lifted their fire to become the forward edge of the barrage, and the pattern was repeated to keep the barrage rolling forward without ever ceasing.
As you can tell the main point here. Use power attacks that will do nothing but weaken the enemy so that you may move forwards.

Objective: Push out with a bunch of light armed troops to die for their liege and lord, then follow behind with your main line. This means no more leap frogging between cities. When you do an attack you hit every city on your border with a light cavalry/infantry/artillery and then the very next turn have your main line meet the enemy while your weakened light assault forces pull back to re-supply.

Do's: Use it in actual battle, for that would be cool to see.

Don'ts: No more attacking individual cities, it has become a version of WW1 in your game where you attack along the line instead of select spots.

Strategy number 2, lets see how many do this.