It is a method of reading only selected portions of material in order to obtain knowledge of the general ideas and major supporting details. It is not a casual, haphazard process in which the reader winds up with only a vague idea about what s/he has read. It is a highly selective process requiring intense concentration and constant analysis and integration of those portions of the material that are read.
Skimming is useful when you want to survey a text to get a general idea of what it is about. In skimming, you ignore the details and look for the main ideas. Main ideas are usually found in the first sentences of each paragraph and in the first and last paragraphs. It is also useful to pay attention to the organization of the text. As reading is an interactive process, you have to work at constructing the meaning of the text from the marks on the paper. You need to be active all the time when you are reading. It is useful (http://www.topessayservices.com/); therefore, if you need to read the text in detail, before you start reading to activate the knowledge you have about the topic of the text and to formulate questions based on this information. Skimming a text for gist can help you formulate questions to keep you interacting with the text.