interaction while reading

There are many strategies and skills of reading foreign-language texts. As I've learned so far, those skills/strategies interact each other when the learner is reading any kind of texts. In that sense, I thought about my reading habits. What skills do I use?
I concluded It depends on the type of the text and the purpose of reading. For example, when I read textbook for preparing *quiz* something, I always read along the bottom-up processing and spend all the time to understand every word, sentence, and whole paragraph and try to memorize all of them. In the case of reading for killing time, on the other hand, I usually do skimming and read in perspective to catch out the main theme and whole meaning.
And the truth is that these stratigies are often used at once.