Quoi, qui, que, ce que, ce qui, est-ce que, and qu'est-ce que

• "Quoi" is used as the object of a preposition (i.e.: à, avec, après), except for variations of "de". Example: Sais-tu à quoi il pense ? = Do you know what he's thinking about?

• "Qui" can be most easily translated as "which", or "who". It's used when referring to a specific item or person doing something (La chienne qui aboye), or when asking a question (as in "Qui aimes-tu").

• "Que" can be used to compare something (he eats more than she eats = il mange plus qu'elle mange), or to be used to say "that" ("he thinks that he eats a lot" = "Il pense qu'il mange beaucoup").

• "Ce que", and "ce qui" are indefinite pronouns. Ce que is used to describe something the subject of a sentence is modifying, and ce qui describes the subject of a sentence.

This is what he wants = "C'est ce qu'il veut". This is something that satisfies me = "C'est ce qui me satisfait."

• "Est-ce que" is a phrase placed in front of a statement to make it a question.

"Tu l'aimes" = "You like it." In French, when describing the subject of a sentence in relation to another object or place, the subject goes first, then the pronoun of the object or place being related to, and then the verb. "Est-ce que tu l'aimes ?" = "(Do) you like it?"

• "Qu'est-ce que" means "what is it that", as in "What is it that he likes to eat" (Qu'est-ce qu'il aime manger ?) Similarly, "Qu'est-ce qui" means "What is it that", however, just like "ce qui", it refers to a subject instead of an object. ("Qu'est-ce qui aboye ?" = "What's barking?")

tout, tous, toute, toutes

"Tout", when used as an adverb, always stays invariant. When used as an adjective, it agrees in gender and number with the noun it modifies (like every adjective in French).

Example:
Ils sont sales means "They are dirty". Adding tout gives a complementary information, different whether tout is employed as an adverb or an adjective:
Ils sont tout sales. (Adverb: invariant). Insists on the adjective sale. In this case tout means "very" or "completely".
Ils sont tous sales. (Adjective: agree with "sales" in gender and in number). Insists on the fact that they are ALL dirty.

false cognates / faux amis

• Actuel vs. actual: "actuel" in French means "current". e.g. les événements actuels = current events
• Sale vs. sale: in French, "sale" is an adjective that means "dirty". eg. des sales = some dirt
• Travailler vs. to travel: "travailler" is a verb meaning to work, not "to travel".
• La librairie vs. library: "librairie" denotes bookstore.
• La figure vs. figure: "figure" in French means face.
• La journée vs. Journey: "journée" in French means day.

ap/em/porter

apporter - to bring an object (only things you can carry) to a place where you are. J'ai apporté mon livre à la fête.

emporter - to take an object (only things you can carry) to a place different than your current location. J'ai emporté ma boisson à la fête.

Best way to remember is that 'take' has an 'e' so the verb starts with an em.

a/em/mener

amener - to bring an animal, vehicle or a person with you to a place where you are. Si vous venez nous voir, amenez votre frère.

emmener - to take an animal or a person with you somewhere different than your current location. Il a emmené ses enfants à l'école.

Same formula to remember: 'take' has an 'e' so the verb starts with an em.

passer

• passer la journée which means to spend the day (doing something. a longer example is needed here)
• se passer which means for something to happen, or to occur.

pronominal verbs with meanings different than regular version

• s'en aller
• s'en vouloir
• s'enfuir
• s'envoler

plus

Plus can mean "more" or "not anymore" according to the context. The final "s" is pronounced only when it means "more"

capitalization

The days and months names are always in lowercase (unless they begin a sentence):

• lundi = Monday.
• janvier = January.

bon vs bien

• Bon is usually an adjective. It modifies a noun and means good, suitable, efficient, correct, useful, etc.
• Bien means good, right, healthy, etc., and can often be used as an adjective with the verb être. It usually is an adverb, however.

an vs année

• an is a masculine noun meaning "year".
• année is a feminine noun meaning "year".

jour vs journée

• jour is a masculine noun meaning "day"
• journée is a feminine noun meaning "day"

negation other that ne... pas in detail

Pas can be substituted for other words to give a negation new meanings. For instance, ils ne regardent pas - "They are not watching" can become:

• Ils ne regardent plus - They are no longer watching
• Ils ne regardent guère (formal) - They are barely watching
• Ils ne regardent jamais - They are never watching

c'est vs il est, ce vs il vs one

C'est means this is. For example, saying C'est le chien would mean 'This is a dog'.

Il est means it is. For example, saying Il est malade means 'He (or it) is sick'. Note that est is the il form (present) of the verb être, which is a 3rd group verb.

mal, le mal, faire mal, malade, malaise, etc

ger and cer verbs

Verbs like manger(to eat) and commencer(to start) have a slight deviation in the nous form for these verbs.

For verbs like manger, which use the ger ending, add an e to the nous form in front of the g of 1st group verbs - that is nous mangeons.

For verbs like commencer, which use the cer ending, add a cedilla(Ç) to the c in commencer - that is nous commençons.