Work harder at the beginning of the semester. Then, at some point during the semester everything will start to "click" and the amount of work you have to do will taper off. If you don't put in the time at first, you will always be playing catch-up and it will just get harder as you go along.
Make flash cards. Use them for definitions, molecular structures and short-worded theories. Keep your flash cards with you at all times, so you never have an excuse to not look at them.
Go to every class having already read the material in the book. This way, you can ask questions and focus on what you don't already understand.
Form study groups and commit to meet at least twice a week. Make it a point to not only learn from your study partners, but to explain things to others who may not understand. Teaching a subject is the best way to learn it.
Stay calm during the exam. Skip over questions you don't know right away and start with the ones you do understand. Don't let your confidence be undermined right from the start. Most of what you need should be in there somewhere even if you just attended classes and didn't study much.