Over the last decade, I've seen students succeed, and others struggle. While every situation is individually unique, the shared problems – and their solutions – are almost always the same:
Time management is the most valuable skill you have; procrastination, your worst enemy.
Moderation in everything, including moderation. It is extremely tempting, especially if you are a student living away from home for the first time, to party hard and come into class later. Class is work, and work is your priority. Have fun, but be aware of your responsibilities.
Use the resources of your institution. For example, SAIT Polytechnic has counseling services, health services, faith centers, student tutoring and groups. Help is there for you, but you have to choose to use it.
Consider very carefully the commitment you give to sports, hobbies, and most especially full and part-time work. How you spend your time is up to you, but the choices that you make will not be accepted as excuses for poor work in class.
Backup your work. Backup your work. Backup your work. (I have an hourly backup of all of my systems and files at home, a weekly backup of those files stored at my office, and monthly backup stored in a bank vault. Short of a large M-type asteriod hitting Calgary, I will always have access to my files.)
If you have issues with your instructor, meet with them first, no matter how intimidated you might be. You may not get the answer you want, but at least you have paid them the courtesy of informing them of the issue and listening to what they have to say. Trying to "jump the line", escalating your issue without talking to the instructor, blindsides the faculty and immediately creates bad blood. If you don't get the resolution you want from your instructor, then work up the chain of command (team leader, academic chair, dean).
If you are 18 or over, you are an adult: I will not meet with your parents to resolve an issue you have in class. If you are an adult, behave like one. (Think of it this way: would you bring in your mother to talk to your boss if you got a poor work performance evaluation? If the answer is no, why try to do it here?)
Remember that your instructor cannot judge your work based on the effort you feel you have put in, how hard you have tried, or the hours you have spent. All the instructor can evaluate is what you give them. That work will and must be judged on its merits, not your own. It is natural to invest your ego in your work, and identify with it, but you should not feel that a poor evaluation of your work is necessarily a reflection on you.