Don’t use 10 words when you could the say the same thing in five. (Remember, each word is a gift—don’t waste a single one).
Don’t use SAT vocabulary just to show off. (We know you’re smart!) If a five-syllable word throws off the rhythm of the writing or worse–causes the reader to stumble, you’ve gained nothing.
Use an active voice, rather than a passive one (The student took the test vs. The test was taken by the student).
No need to find a myriad of synonyms for the word, “said,” when incorporating dialogue.
Don’t go crazy with adverbs—show your reader rather then tell them. (Also trust your reader’s ability to infer).
Make sure your noun-verb agreement is correct. Obviously, spell and punctuate correctly too.
Maintain one consistent verb tense when telling your story: simple present, simple past, present-perfect, past perfect continuous, etc.
Know the difference between their, there, & they’re; your & you’re; its & it’s; to, too & two, etc.
There is no such word as supposably (it’s supposedly).