Here's my situation: I'm a computer science student who has taken Calculus I twice. Not less than a week ago, I finished a second semester of the class and felt entirely defeated finishing the final. I've never felt a proficiency in Algebra, Geometry and Trig, and my professors have always said that a successful Calculus student needs to master those subjects before trying to take on Calculus. Therefore, after reading many of the questions on MSE, I've noticed two different approaches. (1) My initial approach, I would pick up textbooks on Algebra, Geometry and Trig. so that I can be prepared for Calculus or (2) I can pickup a Calculus textbook (I don't really like the one we used last semester by Stewart) and actively study from that and ask questions when I can't figure something out. My question is, being that some or many of you have gone through this, what would be the best approach to be prepared for and eventually master Calculus? I don't want to continue making the same mistakes and seeing as I have relatively long Summer, I would like to take the time to fix them.
Also, I do apologize if this is too general of a question, or is not specific enough. I know that similar questions have been asked consistently but I don't believe that this specific question has been, feel free to tell me otherwise though.
Conclusion
I didn't expect such a quick response! Thank you all for answering my question. So far the consensus is mixed. Therefore, I've decided that I will try to review Pre-Calculus (Algebra, Geometry, Trig.) in more or less a month's time frame before tackling Calculus. Then, I'll use resources such as Khan Academy, MIT Open Course Ware, PatricJMT and definitely MSE while studying Calc. I can finally start studying, haha.
I feel the thing that helped me the most was to read the material before lecture and then do the questions in the book. Once I could do a type of problem with ease, I'd move on to the next type of problem. So I would recommend your second option: pick up a good Calculus book and read and work on the problems.
Edit: As Armin has suggested, I also recommend supplementing your knowledge with videos as well. Sometimes when the book seems to be unclear a video can be very helpful. Armin has suggested the MIT videos, and Khan Academy. I would like to also add PatrickJMT to that list. Since they are videos you are free to go at your own pace and can pause them if you didn't understand a concept they were discussing.