The SAT is a stressful test, what would you recommend to a student to prepare for such a long and challenging test?
The SAT test is definitely long and definitely challenging. But, because the test is predictable you can prepare yourself to know what is coming. As a student if you know what the test is going to ask you and the format in which it will test you, you can enter the test confident in your preparation.
Is it more important to be solid on subject knowledge (memorization) or test taking strategy for the MCAT.
With the changes in the new MCAT it has become more important to learn test taking strategy and passage analysis than memorizable facts. Although conceptual information is still extremely important, in personal experience I have seen that passages on the new style MCAT are long and require thorough critical reading to do well on the subsequent questions. Rarely will you find standalone questions asking for regurgitation of information.
What do you think is most important in putting together a college application.
Likely by the time you are beginning to write college applications your file/resume is closed, meaning that the experiences and extracurriculars that you have can no longer be added to. Therefore, the most important part of the college application is unifying the experiences and strengths in your application. In short, creating a unique story and theme to define one's self in the application will allow you to stand out to admissions committees.