Don't hesitate to ask questions in class. If you have to miss class, be sure you know of any changes made to the syllabus or of any material discussed such as cultural information which may not be in the book or which has been explained by the instructor. Take advantage of every practice opportunity such as doing lab manual exercises, practice tests in the grammar book, videos in the library, cultural or club events, etc . Get an attitude about homework. If you take the time to get it right, not just settle for answers you are not sure of, you will learn much more.
Every student has a different way of learning material.
Some learn better by writing out the vocabulary and other material. One technique some students find useful is to list feminine words in one column and masculine words in another. Nouns should always be memorized with their corresponding definite or indefinite article so as to know gender. Writing out verb tenses may also be useful. Writing a few original sentences using the new verbs, vocabulary and grammar just studied and then having your instructor check these during office hours is another useful tool.