Come up with a plan of what you're going to do to differently this semester. Stick to that plan.
Speak with advisors. They can give you some really good advice about steps you can be taking now to improve your G.P.A.
Manage your time wisely. When ever you have free time, or time when you're just bored, use that time to get things done. This can take a load off of your hands from things you may need to do later.
Keep your priorities in mind. School comes first before everything else. Get things like homework assignments, studying and reading out of the way before you watch television, play video games, hang out, etc.
Take advantage of tutoring. Usually there's some place on campus that has free tutoring. Use this to your advantage. If you think you need help in some aspect, then seek it. No one will ever know you need help unless you ask for it.
If you feel overwhelmed, talk to counselors. If you feel depressed, you're not alone. There are many understanding people who care and are willing to listen and help you.
Get a good alarm clock. Going to classes regularly is an imperative part of bringing up your grade. Professors go over a lot of important material in class, and you're going to want to be there to hear all of it.
Have a "just do it" attitude.