Can you please give me two aspects of Romanticism that can be found in the poetry of John Keats?

Well, certainly John Keats is defined as the epitome of a
Romantic poet. One aspect that is hard to ignore in his poetry is the predominance of
the imagination. An excellent poem to use to talk about this aspect of Romanticism is
"On First Looking into Chapman's Homer," which talks about when Keats first read a
translation of Homer's Illiad  and how it came alive to him so vividly that he compares
that moment to when new explorers look upon undiscovered
plains:

Then
felt I like some watcher of the skies

When a new planet
swims into his ken;

Or like stout Cortez when with eagle
eyes

He stared at the Pacific--and all his
men

Looked at each otehr with a wild
surmise--

Silent, upon a peak in
Darien.

Note the way that the
imagination is celebrated in this flight of fancy. This is a key aspect of Romanticism,
as the imagination and feeling is always much more important than
reason.

Secondly, you might want to focus on the topic of
beauty as discussed in "Ode on a Grecian Urn." This excellent Romantic ode focuses on
the pictures painted on a Grecian urn and how they cause the speaker to meditate on
beauty and its eternal nature. Note how the poem
closes:

When
old age shall this generation waste,

Thou shalt remain, in
midst of other woe

Than ours, a friend to man, to whom thou
say'st,

"Beauty is truth, truth beauty,"--that is
all

Ye know on earth, and all ye need to
know.

There is a strange
ambiguity in these lines, especially the quote of "Beauty is truth, truth beauty," which
focuses our minds on the way inwhich the quest for beauty is positive in that the
contemplation of ideal beauty gives us an experience of the timeless and eternal, but at
the same time it is negative as such eternal beauty acts as a powerful reminder of our
own ephemeral nature. Such discussions on beauty and its importance to our lives are
another aspect of Romanticism.