Much of the learning process is completely under the control of the student (e.g, reading, studying, practicing examples), however the professor can affect the learing process in three ways: 1) present the material as clearly and logically as possible, 2) provide resources and opportunities to learn outside the classroom, and 3) engage the students.
The first of these can be acheived by careful planning of lectures, handouts, assignments, and other resources. Skills that build upon earlier skills must be emphasized to reinforce the connection and make the material seem more logical. Second, there are always varying abilities among students in a classroom. Therefore, it is important to provide opportunities for learning when not in class, for example, online problem sets that provide feedback, office hours, practice quizzes and exams. Finally, and probably most importantly, student buy-in is essential. I understand that not everyone (and dare I say it, most people) do not share my love for organic chemistry, but showing enthusiasm and using humor during lecture makes it less boring and more likely that someone will pay attention. I have found that the number one way to encourage students to try their best is to show that you care about them and their learning.
Therefore, I try to approach a class as if we are a team. I am the coach. I will instruct my students on the proper techniques to succeed. I will ask students to practice. I will provide additional opportunities for those who request it. I will do the best I can to motivate the team to work hard. The performance of each member of the team will then reflect what she/he did in preparing for the grade. With luck everyone will be proud of their effort and results.