The most important thing to remember in reading this book is to realize it has nothing to do with the movie versions. This novel is more a study of humanity instead of scary thrills. It does help to read summaries, but it is always important to continue reading the text. You will miss nuances, as well as the effect of rhetorical devices in the story that summaries cannot replace.
I counsel my students to maintain a READING NOTEBOOK on every text they read (sometimes I require this). In your notebook you can question the text, actually ask it questions, just as you might ask enotes questions. The accumulation of questions will enable you to discover a pattern that will then in turn help you to answer the questions you have posed. Second, circle the words you do not understand, and in that novel there are many, and look them up. It always surprises me how much difference it makes when I use a dictionary when I read. Finally, organize your notebook so that you leave several blank pages for each character so that you can write down what seem to be important quotations (with page numbers) as you read. As you gather by writing down this evidence, you will begin to understand the characters more. Even better, you will have clear questions to raise in class that your teacher and classmates will be happy to discuss. Teachers always like students to raise questions that will stimulate discussion because everyone profits from that. This sounds like a good deal of work, but that is what it takes to understand a complicated book. Teachers do the same thing.
There are several methods that will help you better understand the book. First, if you are really confused by the language it often helps if you read a brief summary before you actually read each chapter of the book so you know what the action of the chapter will be. You can also check out descriptions of characters or other information. E-notes is an excellent resource for that type of help. Secondly, make sure to read actively and critically, not passively. When you read actively, you check yourself for understanding along the way. I have put referred a web sit here that I often use to help my students learn to read more critically. The beginning of the site is concerned with reading poetry but if you scroll down, there are sectons on reading fiction and particularly on styles of prose within fiction.