Lecturers are guides, they open doors and show paths to knowledge...
...but it is up to you to do the journey. 
Lectures and practical classes are mere introductions, this means that...
...1 hour of lecture should be followed by 2 hours of work involving reading and synthesising information gathered from textbooks and other resources.  Use the web, and make the library your second home.
Become an independent learner but...do not work alone.
Let the lecturers know about your difficulties, concerns and criticisms.
There is no bad students, only bad learning habits.
Most importantly: Get organized, work steadily, and have fun.