Welcome back! I will take you through different words that we all have probably misused at least once in our lives.
lose and loose
Lose's past tense is lost, so you probably know the meaning of it already.
Loose, on the other hand, means that something isn't secure and not tight, like "loosely buckled" and "loosely based on..."
to and too
This is pretty basic. To is a preposition or what infinitives begin with ("to the house" or "to play basketball"). Too means "also" or "in excessive amount" ("I like cake, too!" or "You talk too much")
"I could care less" and "I couldn't care less"
"I could care less" means that you care a lot about something or someone. A lot of people write this when in reality, they mean the second statement. As you can see, you can care less, which means that you care so much that you have a possibility to care less.
"I couldn't care less" means that you literally don't care about something. Your level of caring has gone underground and you don't think it could go deeper into the floor anymore.
exited and excited
Exited is when you leave a place. Excited is when you're eager for something to happen.
Bonus!
Are you having trouble spelling the word "necessary"?
n e c e s s a r y
I've seen a trick on the internet once, and the person explained it like this:
"In a shirt, there is one collar and two sleeves. 1 c and 2 s."
Remember the shirt trick and you won't have to turn your autocorrect on to check the spelling anymore!