Be an Adult
An unfortunate new trend is parents trying to meet with professors to discuss grades and papers. This is a no-no and an absolute pet peeve of all professors. Students should be in charge of their education. They are eighteen years or older and should discuss anything pertaining to their academic career with the professors, an advisor or the Dean by themselves. Only in absolute extreme cases should a parent enter the situation.
If a student is unhappy with a grade or class situation, s/he should make an appointment or drop by the professor's office hours to discuss the situation. Do not have mom or dad call on your behalf. This makes the student look highly immature and disrupts the student and professor relationship. Also, keep in mind, professors talk. If one had a bad parental interaction with you and your parents, the entire department is sure to find out about it.
Lastly, most professors enjoy interacting with their students and look forward to scholarly debates inside and outside of the classroom. If you'd like to learn more on a subject or about a future career, don't hesitate to stop by the professor's office hours to discuss your intended study, a Master's program or even the professor's published works or current projects. Also, if you'd like to be included as a research assistant or Teacher's Assistant (TA) with a favorite professor, get to know the professor outside of the classroom and ask about work opportunities.
College professors' expectations do exceed those of high school teachers. The work and the professors are more demanding in college, but if you forge good relationships with professors, it will only help you in the future.