World War I: German and Allied Tactical Assault Methods Please provide some additional input on the

World War I: German and Allied Tactical Assault Methods

Please provide some additional input on the following
question to further broaden my perspective of WWI:

1 Compare the Allied and German tactical methods of assault
on the Western Front in 1918 with those practiced from 1915 to 1917

2 How do the methods from the two different time periods
compare in terms of casualties for the attacker?