Practice makes perfect, and in the judge's eyes, this speech should be close to flawless. Absolute effiency is important and presentation helps a good bit as well. Depending on the political orientation of the 1AC, differing structures are used to present the content.
For the right (what is traditionally seen as policy debate, claiming things like hegemony, terrorism, etc.)- Inherency- prove that your plan is not in the status quo Harms/advantages- prove that there is a problem now and the reason why bad things could happen is because the plan is not in effect. Plan text- Usually this is formatted by saying the resolution of the year, then state your plan action after it.
Ex. Resolved: The United States federal government should substantially decrease its authority to detain without charge by having the United States Supreme Court overturn Kormatsu v. the United States in the first available test case.
Solvency- this section should be about how the plan is going to be able to stop the harms from happening.
For the left(known better as critical)- usually the inherency is told by reading a story of a person that would be affected by the plan. Next the 1AC launches into a criticism on the way things are now and how we should stop it from happening by implementing the affirmative plan. Usually the plans are questionably topical. Also there is no concrete part of a critical 1AC because the presentation should be entirely fluid.