This is part 1 and only talks about some of the shells. I will make the other parts later.

RED SHELL:
These are shells that home in on the driver in front of the user. A driver hit by one will flip over and almost slow to a stop. Use these to greatly slow your opponent down.

Ways to avoid-
-Red shells are weak and will disappear if they come in contact with another object or a wall. Leaving a lot of bananas on the track (especially near the middle) will help lower your chances of being hit.
-Try swerving to the side near walls. Since their homing isn't all that great you can sometimes cause them to hit the wall (or fall off the track). This method isn't guaranteed to work
-Hold an item such as a banana or a shell behind you. If you are lucky, the shell will hit this instead of you

GREEN SHELL:
These are common shells that lack homing capabilities but can bounce off walls. Although these shells arent' good for much, they can make it a pain to drive correctly. They can also be used as a defense if held behind a driver.

Ways to avoid-
If one or more of these shells are whizzing around, take caution and pay attention to your lower map so you don't collide with one.
-Leave bananas on the track and hope that it hits one.

TRIPLE RED SHELL:
This will give the driver three red shells that circle them until they are hit or used. Be careful not to fire all three at once, because it will be a waste of shells (an opponent can only be hit by one at a time, so the other two would be ineffective).

TRIPLE GREEN SHELL:
This will give the driver three green shells, which circle the user at high speeds. Use this as a defense against opponents or other items. If you choose to fire them, be sure to spred out their paths to make it harder for the opponent to dodge.

(Ran out of room, the spiny shell will be on another part)