I personally believe that the best possible way to strengthen your faith is to investigate it. If you have doubts, that is good. In fact, if you don't have doubts, there is a high likelihood that you haven't really thought about your faith, because there are a lot of things that raise doubts. "Is there historical evidence that Jesus was raised from the dead? Does God really love people? Is what my pastor said in church this morning biblical?" These are just 3 of the hundreds of questions one could have about the Bible, Jesus, church, God, faith, life, love, prayer, etc.
Having doubts and not looking for answers is the best way to have your faith get destroyed the moment you get to your college campus. Also, looking for answers that fit your preconceived criteria won't help either, because you'll likely be forced to ignore facts, and you'll only find the answer that you want; not the one that's right. However, if you look for answers with an open mind, you'll look at all the facts, and when you find your answer, you'll be able to support it if anyone says something different. I thinks thats why so many teens lose their faith once they're in college; they've gone to sunday school and been spoon fed answers, but they've never really answered their own questions. When someone presents a question that they don't have an answer to, they feel there must be no answer.
One thing I've had questions about is baptism. Is it necessary for salvation? Does it guarantee salvation? What does it do? I looked first at what the Bible said; in fact, I wrote down every verse in the Bible with the word "baptize" or "baptism", and then looked at verses that say things like "born of water". Then I looked at what different people and denominations believe, and how they defended their beliefs. I can now, at least well enough for myself, defend my views on baptism, and I will not be totally at a loss if someone were to challenge my views.
I think that you should think critically about almost every sermon you hear or thing you read that relates to faith. Ask questions like, "Is it biblical?" and "Is the scripture they used applied correctly?" I think that we have a great tendency to go to church on sunday morning, listen to the message, and accept it as undeniable truth, without even realizing that we're doing it. I've had many moments where I think, "Yeah, yup, truth..." then an hour later, "Wait a second... but doesn't the Bible say ____ and ____?"
So, in conclusion, the worst possible thing you can do in regards to your faith is not investigate it. Whether you believe or not, ask questions and find answers.