It's easy to improve your college grades if you want to.
ALWAYS attend class and be there early or on time. Sit in the front of the class. Make sure you finish the homework on time and it is as good of work as you are capable of doing. Presentation counts! If work is sloppy, it shows you do not care enough about what grade you get. Make sure you have everything clean, clear, well organized, and looking professional.
Write the name of the class and identifier (IE: CSCI 142 / Java 1) on the name of the spiral notebook for that class.
For every class and every day, date the top of the pages for that day. Write down EVERYTHING the professor says - even if you already know what is being taught and even if you already have it in your notes ten times. Ask questions if something is not clear.
Before the exams, study your notes. If there is something in your notes ten times, it is obvious important to the instructor and will likely be on the exam. Get a good night's sleep before the exam.