Writeability

Starting sentences with"this" or "it" is very vague. When you find yourself writing this way, ask yourself what it is that you are really trying to say. Be clear and specific to the point you are making, if there is another way to convey your message without starting the sentence with "it" or "this"try it out.
Example: This leads one to believe that vacations are most popular in February.

This what? Even if the preceding sentence contains the info needed to understand what "this" refers to, it is best to clarify, ie. This study, This information, etc.

Example: It requires a lot of thought and consideration and should not be entered into lightly.

In this sentence the reader does not know what "it" refers to.