You should try to avoid similar sentences. It's OK to use the word "it" twice if the sentences are different enough. Try to avoid passive sentences like "it was a stormy night" though. Instead, use active voice like "The night was stormy."
To use complete sentences in a paragraph.
yes, it is perfectly fine to write a five paragraph essay on sharks. just don't use run-on sentences or choppy sentences.
so the paragraphs make sense and that the paragraphs link from one to another
The first sentence of a paragraph is normally the topic sentence i.e. it is the sentence that is supported by the remaining sentences.
It is a group of sentences used to discuss one central idea or topic.
As many as you want. However it is not good to make paragraphs too long. Generally one topic for one paragraph. If for example you are doing non fiction writing about a country don't write about the population and industry in one paragraph make a separate paragraph for each topic/subject. If you are doing fiction writing when you move from one scene or action to another the start a new paragraph. A paragraph is a piece of writing consisting of one or more sentences, as many sentences as are necessary, to express a distinct idea or sequence of action, or a quotation of the words of one speaker.
Use your topic sentence as the main idea of your outline and use the details from the supporting sentences.
Limit? That's easy example: this paragraph should be a limit of 5 sentences long
It depends on you - how much sentences you will use. It may be one or few, or more. Remember however than paragraph longer than half of a page looks bad.
When writing a paragraph using chronological order, the use of temporal words is needed. Sentences can include the terms first, next, then, after that, and finally, among others.
use spell check write concise sentences have more than 4 sentences in a paragraph write intelligently proof read
B. pet ownership is a large commitment