"The World is too Much with Us" is a sonnet written (mostly) in iambic pentameter. A sonnet is a fourteen-line poem, the origins of which are attributed to the great Italian poet Petrarch.
There are two main types of sonnets. The Petrarchan sonnet is structured as an octave (eight lines) and a sestet (six lines). The octave often proposes a problem or concern that the sestet resolves or otherwise engages. The ninth line – the first line of the sestet – marks a shift in the direction of the poem and is called the "turn" or the volta (Italian). While the rhyme scheme of the octave is ABBA ABBA, the rhyme scheme of the sestet is more flexible; two of the most common are CDCDCD and CDECDE.
The other major sonnet form is the Shakespearean, or English, sonnet; it also has fourteen lines, but is structured as a series of three quatrains (four lines each) and a concluding couplet (that's two lines right next to each other that rhyme). The Shakespearean sonnet is in iambic pentameter and follows the rhyme scheme ABAB CDCD EFEF GG.
Wordsworth's sonnet is of the Petrarchan variety; its rhyme scheme is ABBA ABBA CDCDCD. In the Petrarchan sonnet there is a noticeable shift in the ninth line (the turn or volta mentioned above). In the ninth line of Wordsworth's poem, the speaker starts to express his wish to be a pagan because he's sick of the way things are; it's getting him down.
For the most part, Wordsworth's poem is in iambic pentameter, which means that each line contains five (pent) feet or groups that contain an unstressed syllable and a stressed syllable (in that order). Take line 10 as an example:
A Pa-gan suck-led in a creed out-worn.
While there are a lot of iambs in the poem, there are also several types of beats that give the poem a sense of variety. Often times, Wordsworth will begin a line with a stressed syllable, followed by an unstressed syllable, as in the first word of line 2:
Gett-ing and spend-ing, we lay waste our powers
(Note that words that end with the sound of "ours," like "powers," are often scanned as one beat in English verse). "Gett-ing" is an example of a trochee. At other times, Wordsworth will use a beat that has two stressed syllables, as in "lay waste" from line 2 above; this is called a spondee.