As an adult person in the world, you should already know the difference between its and it’s; to, too, and two; and their, there and they’re.
For that matter, you should already know affect vs. effect and lay vs. lie. That’s English 101.
What’s that? You don’t remember the difference between affect vs. effect and lay vs. lie? Quick reminder: Affect is a verb, meaning “to influence,” and effect is a noun, meaning “an influence.” Try to remember “cause and effect.” “Lay” means “to put down or set down something”; “lie” means “to rest” (or, you know, to fib). Try to remember, “A chicken lays an egg, and then it lies down.” Making eggs is hard work!
Now let’s skip ahead to the senior-level stuff, the stuff your spell-checker will never catch but you must know.
All right vs. alright
“Alright” is not a real word. Like “a lot” (not “alot”), it’s always two words. All right? All right.
Cache vs. cachet