[Keaton421]

Wa and Ga are similar, you'll learn quickly when to use which one.

Ni indicates where something's located, where you're going, and much more. He means the same as Ni, but I never hear it used.

If your friend says "Watashi wa sushi ga suki" (I like sushi) you can say "Watashi mo" (Me too)

There are many more.

Particles are gonna be your best friend and your worst enemy. After kanji. Screw kanji.