Reading for university is different from reading on your own time. To read academically, you need to read actively. This means engaging yourself more thoroughly with the topic, actively thinking about the author's motivations and making notes on your thoughts, impressions and criticisms. Reading for university is more than just absorbing information. You also need to engage with it, debate it and criticize it. What's more, you need to understand basic things about a piece you read, such as what its argument and main points are.
University classes often take a lecture format, but university is about more than just listening to a professor. You should be prepared to contribute to classes as well, raising your hand frequently, asking questions and voicing your opinion. You should also be prepared for your class -- lectures almost always have required background reading.
Essentially every university course will require written work of some variety. Liberal arts courses generally require essays with well-researched, well-expressed arguments, while science courses generally require lab reports that clearly show how an experiment was carried out, why it was carried out and what its results were. Writing anything at a university level hinges on two things: choosing a topic that interests you (so it doesn't feel like a chore) and carefully planning your argument and points that will back it up. This is all time-consuming, so you should start doing this work as early as possible. In a nutshell, university-level papers are too complex to simply write without a plan. Planning is the key to a successful university career.
Successful test taking is matter of careful preparation. The key point for taking a test is not to cram. If you are trying to absorb an entire semester's worth of information the night before the exam, you are just going to stress yourself and will not likely do well anyway -- there is too much information than can be absorbed in one evening. Rather, you should routinely go over old material, then study for the exam by taking old exams. Ideally, it will be a matter of just studying the exam format -- the raw material will already be in your brain.