Consider the number of classes you attempted versus the number of classes you should take. Perhaps your low grades were due to the fact that you attempted too much in your first semester, and did not allow yourself time to adjust to the various aspects of college life. Take enough classes to challenge yourself in your next semester, but not so many that you will not be able to give each one the time it deserves.
Always attend your classes when scheduled, even if you are allowed a certain amount of absences. You might think that you are not missing anything important, however, you never know what questions will be asked on an exam, and the more classes you miss, the more likely you will not know the answer.
Meet with your professors during their office hours. Be prepared with questions on any assignments you may have. Make the most of your time spent there, and always thank them for seeing you.
Set up a study schedule and follow it. Also, take a learning styles quiz to see what study habits fit you best. Some students need noise, while others require absolute silence. Knowing which traits fit you best will help you create the optimal study environment.
Take time to relax. Remember to take time to have fun on occasion in order to refresh your mind; that way you can get back to studying with a clear head.