In the morning, I went over what I had learned.

Then I had my breakfast.

It suddenly occursred to me that my hair is too long so I had my hair cut at about two.

So I had my hair cut at about two.

This is a sentence fragment so I deleted it and added it to the previous line.

In the afternoon, I will study math and then go to the movies.

I want to watch Avatar 2.

It haslooks like so much fun.

What a colorfull day!

In the US, we don't use the word "colorful" to describe a day.

Then I had my breakfast.

I ate somea few pieces of bread and two bananas.

It suddenly occursred to me that my hair is too long.

So I'll hadve my hair cut at about two.

It haseems so much fun.

In the morning, I went over what I had learned.

Pluperfect/past perfect (past in the past) tense is required because you learned before the morning.

Then I had my breakfast.

I ate somea few pieces of bread and two bananas.

"I ate a few pieces of bread" or "I ate some bread." Use "a few" when the noun is countable and "some" when the noun is uncountable.

So I hadgot my hair cut at about two.

This is somewhat more common in my experience.

In the afternoon, I will'm going to study math and then go to the movies.

"will" sounds clunky in this sentence. "going to" is typically preferred when referring to a planned event/activity.

I want to watch Avatar 2.

It hais so much fun.

Things are fun, people have fun.

The First Day of Mmy Winter Vacation

Only important words in title need capital letter.

In the morning, I went over what I had learned.

"had learned" sounds better than "learned" because you learned something then after that ate breakfast.

Then I had my breakfast.

It suddenly occursred to me that my hair iwas too long.

was not is - past tense.

In the afternoon, I will studyied math and then gowent to the movies.

Past tense needed

I wanted to watch Avatar2.

Past tense - telling a story

It hwas so much fun.

Past simple tense