I believe in a single steps.

or rather; small steps if you mean progression.

I sewed a button to thea cardigan and a make-up bag.

I solved 2 algorithm problems using the approaches like dynamic programming and binary search.

It sounds hard and unclear, but I also only started my way to be developer- - analytic.

In my dormitory there areis a bookshelf, where you can take of leftave the book.

Seldom I go and see onlook at the books.

Today my catch consists inof Haruki Murakami "Dance, dance, dance" and Applied Staticstics.

Each chapter haves an epigraph that for me it isI find to be so beautiful.

I believe in a single steps.

I sewed a button onto thea cardigan, and another onto a make-up bag.

I think this is what you mean? Two buttons on two items.

I solved 2 algorithm problems using the approach like dynamic programming and binary search.

I think this sounds better, but I don't know enough about the subject to be sure that I haven't changed your meaning.

Saying "two" would be a little more formal.

It sounds hard and unclear, but I also've only just started my way/path to becoming a developer-analystic.

In my domitory there areis a bookshelf, where you can take ofr left thave books.

or: "there are bookshelves".

You could also say singular "take or leave a book", but I think plural sounds better.

Seldomometimes I go and see onlook at the books.

I don't think "seldom" is right here. I'm not sure how to define it. My attempt: "seldom" is like you're emphasising that you do something less than might be expected, or less than others. Examples: "My father's grave was a depressing place. I seldom went there." "I was expected to send a status update to my boss every day, but I seldom did so."

"see on the books" sounds wrong. "see what books are there" / "see what's on the shelves" / "browse the books"

Today my catch consists inof Haruki Murakami's "Dance, dDance, dDance" and Applied Staticstics.

Each chapter have(of Marukami's book) has an epigraph that for me it is soI find beautiful.

Each chapter is singular, so "has".

The ending is a little clunky. Alternatives: "an epigraph that is beautiful to me" / "an epigraph that to me is beautiful" (this doesn't sound quite as natural to me).