Lecturers organise knowledge into a coherent format, they emphasize links between what may appear as unrelated information, they develop fundamental concepts and show how natural processes are related to these concepts.
In a sense Lecturers are guides, they open doors and show paths to knowledge
...but it is up to you to do the journey.
Learning is your responsability.
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 synthesizing 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 asap about your difficulties, concerns and criticisms.
There is no bad students, only bad learning habits.
Most importantly: Get organized, work steadily, and have fun.