To write such an outline, you would first need a thesis statement. What main difference or similarity would you like to discuss? For instance, both Tennyson's "Ulysses" and Shelly's "Ozymandias" involve the theme of time. An example of a thesis statement using this idea might be the following: Although both poems concern man's relationship to time, Tennyson's "Ulysses" stresses the importance of making the most of what time we have while Shelly's "Ozymandias" focuses on our insignificance in the entire spectrum of time.
Other thesis statements might involve man's relationship to his life's work or the idea of reputation. Whatever you choose, make sure that your thesis statement is broad enough to have several sub-points. These sub-points will become your topic sentences for your outline. When you write your essay, you will develop paragraphs supporting these topic sentences and relating them to your thesis statement.
A sample topic sentence outline might be something like the following:
I. In each poem time is introduced by references to the superiority of the past over the present.
A. In "Ulysses" the past is described in terms of the adventures that Ulysses and his fellow mariners enjoyed.
B. In "Ozymandias" the past is described implying the former might of the pharaoh and the vastness of his works.
C. In "Ulysses," the present is contrasted with the past as boring, tedious, and ineffective.
D. In "Ozymandias, the present is contrasted with the past through images of ruins that now occupy the space once populated with grand works.
II. The effects of time are presented differently.
A. In "Ulysses," the title character tries to make the most of his time by deciding to go on one last adventure.
B. In "Ozymandias" time makes a mockery of the titled character by showing that his works did not endure.
And so on...
You can do something like the above with any topic you think is interesting about the two poems.