The SAT I has 7 sections, with 3 math sections and 3 verbal sections, plus a "wild card" section of either math or verbal. Even though the wild card section doesn't count toward your score, you have no way to know which section the wild card is, so you must do your best on all the seven sections.
Each section is timed to take either 15 or 30 minutes. The whole test will take you three hours to complete. The following table gives you an idea of what to expect, though the actual order of sections can vary.
 Section  # of Questions  Time 
1.  Verbal Reasoning  30 or 31  30 min. 
 Sentence Completions  9  
 Analogies  6  
 Critical Reading  15  

2.  Mathematical Reasoning  25  30 min. 
 Standard MultipleChoice   
 Mathematics   

3.  Verbal Reasoning  35 or 36  30 min. 
 Sentence Completions  10  
 Analogies  13  
 Critical Reading  12  

4.  Mathematical Reasoning  25  30 min. 
 Quantitative Comparisons  15  
 GridIns  10  

5.  Wild Card Section  varies  30 min. 

6.  Verbal Reasoning  12 or 13  15 min. 
 Critical Reading   

7.  Mathematical Reasoning  10  15 min. 
 Standard MultipleChoice   
 Mathematics   
Except for the Critical Reading problems, the questions are designed to get rougher as you work through a set. The charts below are typical examples of the patterns of math questions.
As you work, you should always be aware of where you are in the set. When working on the easy problems, you can generally trust your first impulse  the obvious answer tends to be right. As you get to the end of the set, you need to become more suspicious about your answer because they probably won't come easy. If they do, look at the problem again, because the obvious answer tends to be wrong.
To move through the test efficiently, you are allowed to skip around within each section. Do not spend too much time on any one question, even a hard one, until you've tried every question at least once.
There are some rules about how you can and can't allocate your test time:
 You are not allowed to jump back and forth between sections.
 You are not allowed to return to earlier sections to change answers.
 You are not allowed to spend more than the allotted time on any section.
 You can move around within a section.
 You can flip through your section at the beginning to see what type of questions you have.
