は

わたし は ふとています

Indicates the subject by coming after it.

 (Think of is, am, or are)

"I am fat"

の

わたし　の　なまえ　は　こういち　です

Makes something possessive

(Think of Apostrophe 'S' or 'of') 

"My name is koichi"

も

わたし も

Means also / too

(Can also emphasize "any")

"Me too"

を

すし を たべます

Indicates the direct object

(Think of the order "Noun - Particle - Verb")

Eat sushi

に

わたし　は　にほん　に

いきます

Indicates what an action is directed to, destinations, directions, places, and times.

(Use this particle when you use your 'knees')

"I will go to japan"

へ

にほん　へ　いきます

Emphasizes the destination

(Think of "heading towards")

"Heading towards japan"

で

くるま　で　いきます

Can show how or where an action takes place

(Think "By way of" or "at")

"I go by car"

か

わたし は ふとていますか

Indicates a question

(Acts like a question mark)

"Am I fat?"