Do I need to take the SAT or ACT?
Ultimately, each student needs to take either the ACT or the SAT for college admission purposes. A related question has to do with whether students should take both. Honestly, that is entirely up to the student. More anecdotally than anything else, some students seem to perform better on one than the other. But over time, most students tend to score similarly on both tests. Again, we encourage the student to make that final decision.

When should I take the test for the first time?
Students should never take the official test for practice purposes. Given that several highly selective colleges require students to submit all test scores, it is not in any student’s best interest to take the test prematurely. Our strong suggestion is to take the SAT I for the first time in March of the student’s junior year. That leaves multiple future dates for the student to take both the SAT I and the SAT II Subject Tests. Keep in mind, too, that students tend to do better on standardized testing the more mature they are. By March of a student’s junior year, they are usually at a place in both their mathematics and English courses to do well on the test. Students tend to take the SAT I for the second time in October of their senior year. If a student feels like he or she needs to take it for a third time, the test is offered again in November. Similarly, if a student decides to take the ACT, February or April of junior year is a good time to try the official test.
What happens if my testing never results in scores I am happy with? 
Not every school requires the SAT or ACT.  Some schools accept alternative testing requirements, or no testing all together.  Consult for more             information. 
I am applying to university abroad-do I still need to take standardized tests?
Yes!  In fact, students who are interested in going to college overseas, especially in the UK, should plan on sitting for as many standardized tests (SAT, ACT, Subject Tests, and AP exams) as possible. 

Should I take test prep, and if so, when?
Here is what we suggest: wait until the results of the PSAT come out. We realize this will take some patience, both for the student and the parents of that student. After receiving the results, the student can determine which area(s) need some attention. At this point, students might choose to enroll in a test prep course. If a student does, remember what was mentioned earlier regarding timing of the first sitting of the SAT. Essentially, the student has three months to prepare for the SAT I after receiving the PSAT results. We believe that provides students plenty of time to prepare for the test. Many students benefit from taking timed tests on their own. Not every student needs to take a test prep course.
Athletes hoping to be recruited should plan on taking the SAT in January or March or ACT in February. 

SAT Subject Tests (SAT IIs)

Not every college requires SAT Subject Tests, but enough do that we strongly advise every student to take at least two SAT Subject Tests by the end of junior year. Only one school in the US (Georgetown University) requires three Subject Tests.  Although not every student will need to send Subject Test scores, we would not want to see any student in a position where they cannot apply to a college of interest because they had not satisfied the university's testing requirements.  Students are encouraged to play their strengths and to scour websites for individual college's specific testing requirements.  Applicants to specific programs (i.e. engineering) may need to take specific Subject Tests.

For those students who plan on taking subject tests, we advise them to focus on their core academic strengths and competencies. Just because a student can take a test does not necessarily mean that they should. For example, if a student completes biology during her freshman or sophomore year, the student should not feel obligated to take the SAT Subject Test in biology. Rather, we encourage the student to think about their entire high school curriculum and to consider which two subject areas reflect their academic strengths and competencies. If biology happens to be one of those areas, and that same student does indeed have an interest in potentially pursuing biology or science as an undergraduate, then biology could be a great choice. But no student should feel like they have to take the test just because they completed the course. Before making a final decision, we encourage every student to seek advice from both their teacher and one of the college counselors. This should ensure that every student makes an educated decision in advance of taking each test. It is important to note, too, that not every course prepares students for the actual test, at least not entirely. The curriculum of the course does not necessarily reflect the content of the subject test. Students need to take the time to determine that discrepancy so that there are no surprises.

We also encourage students to wait until the appropriate time to take one or more of the subject tests. If a student is enrolled in Algebra II as a sophomore, for example, it doesn’t make sense for that student to take the SAT Subject Test in math at that time. If the student knows she will take Pre-calculus the following year, for example, then waiting makes all the sense in the world. The same is true for a student who plans on taking one of the language tests. We discourage students in that situation from taking the test prematurely. As a side note, students must choose between taking a language test with or without a listening component. All of this is clearly outlined on the College Board web site

Testing Resources
Each of these sites has sample questions for the tests, as well as full copies of tests. These sample tests can help you determine on which subject tests you are likely to perform best.