Hi dDear,

Always capitalize "Dear" when you start a letter.

Yesterday , mMy older sister wais coming for stay with us for two days.

You could also say, "Yesterday, I learned that my older sister will be coming to stay with us for two days."

My nieces and my

Today, I haveI spent time with her, today, and she has talked about his boss...etcer job and her boss, among other things.

This sentence doesn't need to be in present perfect, but you can use it if you want to!
I also added "her job and her boss" for more clarity about what you and your sister talked about.

Yesterday, I reviewed ther present perfect tense and I did three excercicses.

well, but I always have difficulties when I wroite a letter.

I would like to say, I always read short and long textes in English.

and especially I keep your words, but I have not been getting results. That's all for today.

Hi dDear,

Yesterday , my older sister was coming forcame to stay with us for two days.

Today, I have spent time with her, she has talked about hiser boss...etc.

Yesterday, I reviewed ther present perfect and I did three excercices.

well, but I always have difficulties when I wroteiting a letter.

I madke mistakes.

I would like to say, I always read short and long textes in English.