'The Elements of Style does not pretend to survey the whole field. Rather it proposes to give in brief space the principal requirements of plain English style.'
Design - choose a structure in advance, when planning what to write, and hold onto it.
Paragraphs - the primary compositional unit of writing. Each paragraph should be about an individual topic or speech. Begin paragraphs with a sentence that gives the topic or helps with the transition. Break paragraphs apart if it helps the reader, not just for the hell of it.
'After the paragraph has been written, examine it to see whether division will improve it.' (Page 32)
Active voice - it's much better to use the active voice in most cases. E.g.:
Makes for much more feasible writing. Passive shouldn't always be discarded, though—sometimes you want to determine the subjective and mood and the passive voice will help you do that.
'Brevity is a by-product of vigor.' (Page 34)
'Not' - say what things are. Don't waste your time saying what they are not.
Be definite - do not dance around the truth express it in concrete terms.
Omit needless words - 'this is a subject that' can better be written as 'this subject'.
'"The fact that" is an especially debilitating expression. It should be revised out of every sentence in which it occurs.' (Page 39)
Summaries and Tenses - in a summary, or anywhere really, pick a tense and stick to it, otherwise you'll confuse the reader.
Emphasis - put the word or words you want to emphasise at the end of a sentence.
Strunk/White include guidance on:
'The shape of our language is not rigid; in questions of usage we have no lawgiver whose word is final.' (Page 63)
This is the biggest chapter, some of the below are the ones that I found the most useful; interestingly, they're mostly homonyms.
Compare to/with - comparing to something is to find the similarities in things that are of different orders (e.g. work has been compared to a marathon, not a spring). When you are comparing with something, you are finding the differences in things that are similar (e.g. Cambridge, MA can be compared with Cambridge, England and The Lion King musical can be compared with the original Disney film).
Disinterested - disinterest is impartiality. Uninterested is not interested.
Farther/Further - farther relates to distance. Further relates to time or quality.
'Finalize. A pompous, ambiguous verb.' (Page 72)
'The use of like for as has its defenders; they argue that any usage that achieves currency becomes valid automatically. This, they say, is the way the language is formed. It is and it isn't. An expression sometimes merely enjoys a vogue, much as an article of apparel does.' (Page 79)
Nauseous/Nauseated - nauseous is sickening to contemplate. Nauseated is literally being sick to your stomach.
Partially/Partly - the former is continuous, the latter is discrete (often with physical objects).
Respective/Respectively - these two can usually just be omitted!
'The formula to express the speaker's belief regarding a future action or state is I shall; I will expresses determination or consent. A swimmer in distress cries, “I shall drown; no one will save me!"' (Page 86)
Transpire - means that something has become known, not that it has come to pass.
'Why say "utilize" when there is the simple, unpretentious word use?' (Page 77)
'Here we leave solid ground. Who can confidently say what ignites a certain combination of words, causing them to explode in the mind? Who knows why certain notes in music are capable of stirring the listener deeply, though the same notes slightly rearranged are impotent?' (Page 97)
A handful of selected guidelines that felt important to me.
Put yourself in the background - don't show up deliberately in the text, achieve style by affecting none.
Keep it natural - do not imitate. You will do that anyway, subconsciously.
Have a plan - know what you're getting into, the scope and scale of the work.
Nouns and verbs > adjectives and adverbs - one is tough, the other is weak.
Revise and rewrite - from tinkering to major surgery, it's all necessary to some extent with everything that you will write.
'It is always a good idea to reread your writing later and ruthlessly delete the excess.' (Page 106)
No overwriting - simply put, don't overdo it. Do not elucidate your verbiage with whimsical vocabulary. Use short, simple words.
Be sparing with opinion - make your point convincingly. That should be enough. Any more is ego.
'The beginner should approach style warily, realizing that it is an expression of self, and should turn resolutely away from all devices that are popularly believed to indicate style-all mannerisms, tricks, adornments. The approach to style is by way of plainness, simplicity, orderliness, sincerity.' (Page 100)