Writing good philosophy is not easy. Fortunately, there are a number of excellent online resources to help you improve:
An excellent basic guide to writing philosophy papers, with helpful examples and templates.
This beautifully produced Prezi by Angela Mendelovici allows you to scroll through a sample philosophy paper with helpful notes highlighting key writing techniques.
If you're looking for a more in-depth writing guide that will also help you with your writing in classes outside the philosophy department, we strongly recommend They Say / I Say: The Moves That Matter In Academic Writing, by Gerald Graff and Cathy Birkenstein.