LOG:
I agree with the analyses and advice given by others in the thread. The method shown by Prienne is a good one to begin studying and understanding meter. Look at individual words; see how you pronounce them in conversation; note which syllable has greater stress. I also suggest you try pronouncing them unnaturally so as to see the difference. In the 'thunder mister prefer straighten' sequence try pronouncing them wrong:
thun DER mist ER PRE fer staight EN
See if that helps. Consider the words 'angel' and 'angelic'. Angel is pronounced AN gel and angelic is pronounced an GEL ic. So if you want to work these words into a poem with iambic meter, you have to get the phrasing right to have them in the right place.
The angel told her she'd give birth.
the AN gel TOLD her SHE'D give BIRTH
Angelic hosts proclaimed his birth
an GEL ic HOSTS pro CLAIMED his BIRTH
Can you see this difference, and hear the meter?
I have noticed that syllables with long vowels tend to take more stress than syllables with short vowels. I've never seen that stated in a poetry textbook, so consider that merely the observation of an amateur practitioner.
Also, the role the word plays in a sentence has a big impact on its stress. The main nouns and verbs (subject and predicate, or it is subject and object? too long since English class) tend to take more stress than pronouns, conjunctions, and prepositions. Modifiers can go either way. This is true for one syllable words. Thus the stress of a word may change depending on its function in a sentence, especially for pronouns. Consider this line from Frost's "The Road Not Taken":
And I, I took the road less traveled by
and I/ i TOOK/ the ROAD/ less TRAV/ eled BY/
iamb/iamb/iamb/iamb/iamb/
The first "I" gets much more stress than the second "I" because of it's role in the sentence.
When stringing words together in a line of iambic meter (or any other meter for that matter), you also have the phenomenon that syllables appear stressed or unstressed not only based on their instrinsic characteristic but also because of adjacent syllables. You have strong stresses and weak stresses; you have strong unstresssed syllables and weak unstressed syllables. Any of these can exhibit their less dominant character when flanked by different syllables. In the Frost line, the second "I" is between a strong "I" and the main verb, "took". "Took" takes more stress therefore, making the second "I" seem weaker and fulfill the function of an unstressed syllable. In the Wordsworth line quoted up-thread:
I wandered lonely as a cloud
the preposition "as" is very weak, and would not take much stress in normal speech. But here it is, with "-ly" on one side and "a" on the other. "a" is about as weak as they come, so "as" will seem stronger. However, "-ly" is a fairly strong unstressed syllable, having a long vowel. Yet, as the second syllable of "lonely" it is somewhat demoted in normal speech. Thus the reader has no trouble slightly promoting "as" to be stressed, making the line feel iambic, if weakly so. This is natural iambic speech. The second of the Wordsworth lines quoted:
That floats on high o'er vales and hills
has no such problems. Every word is a single syllable word, yet every word takes or gives stress according to its use in the sentence, whether its vowel is long or short, and the strength of the syllables that surround it.
I had some more examples, but I think my employer wants me to start earning my money on time. Accursed day job!
Best Regards,
NDG