Don't confuse ALMOST with MOST!

[english grammar man]

Most + a plural noun = the great majority of. It's used for general statements. (Statements with wide application).

Example
Most cars have four wheels. = 70% to 90% of cars have four wheels.
Most birds can fly. = Birds, except for penguins and a few others, can fly.

Most of + a specific group = the great majority of that group. It's for more specific cases. (More narrow applications).

"Most of" is also used with possessives.

Example
Most of my friends live in Tokyo.

"Most of" is also used with: the, this, that and those.

Example
Most of the people in China are poor.

Almost is an adverb. It is used with a verb to mean "very nearly" or "just about".

Example
It's almost 3pm. = It is 3:55, 3:58 etc.
I almost had a heart attack. = I came close to having a heart attack.

Here is another pearl of wisdom for you English teachers out there. We never say almost with a noun or an adjective to mean "most", so:

Example
"The people in my section are almost women." should be "Most of the people in my section are women."

NOTE: We can say "almost all" to mean "most" sometimes. It usually means around 99%.

Example
He gambled almost all his money away.

Happy teaching!