Grow Your #Vocabulary: This post has been brought to you by the Letter I

Four sets of words commonly misspelled, misused, or confused.

its: The possessive form of it.
vs 
it's: Contraction of it is.

imply: To express or indicate as a hint. To suggest without being explicitly stated.
vs
infer: To conclude (a state of affairs, supposition, etc) by reasoning from evidence, deduce. To have or lead to as a necessary or logical consequence.

insure: To guarantee against loss or harm. To secure indemnity to or on, in case of loss, damage, or death.
vs
ensure: To make certain or sure, guarantee. To make safe or secure, protect.

Above definitions via The Free Dictionary

I: "Use I along with other subjective pronouns such as we, he, she, you, when the pronoun is the subject of the verb".
vs
Me: "Use me along with other objective pronouns such as him, her, when the pronoun is the object of the verb".

Use of I versus Me via Oxford Dictionaries

Yep, just me Cathy thinking out loud about the letter "I".