Well, it depends on the sentence and the idea you're expressing. I'm assuming you are talking about writing sentences where you are talking about yourself, but you just don't want to write "I" all the time at the beginning. I'm also assuming you're not talking about writing questions, but about writing regular statements. --- In the examples below, the basic idea is the same, but the wording and tone are different. -I will buy groceries tomorrow. -> Tomorrow I will buy groceries. -I opened the door and found the mail on the ground. -> When I opened the door, I found the mail on the ground. -I think elephants are great animals. -> Elephants are great animals, in my opinion. OR-> In my opinion, elephants are great animals. -I found a book. -> A book was found by me. "A book was found by me." is in the passive voice; "I found a book." is in the active voice. To me, the passive voice doesn't sound very natural here. -I was bit by a dog. -> A dog bit me. "I was bit by a dog." is another example of the passive voice (and it sounds natural in this example); "A dog bit me." is in the active voice (also sounds natural). If you have questions about the passive voice, let me know, and then I can explain more. --- Basically, here's how I see it: -Using "I" at the beginning of the sentence is the most common and direct way of getting an idea across; that's how I write, at least. -Even if you are speaking about yourself or something that happend to you, the subject isn't always "I". ("A dog bit me." for example.) -Passive voice can sometimes sound unnatural, but not always. Hopefully I understood your question. I'll stop explaining here; let me know if you have any questions. Also, let me know if this wasn't the kind of answer you were looking for, haha. :)

strange! you mean without the pronoun (I) as a subject? choose any subject you want in imperative sentences , no subject

You ?

You change the subject of the sentence. You only need I when you talk about yourself, but you can use any other subject when writing. You wrote a sentence starting with "How" so in a way, you answered your own question :)