Let me start of by commiserating with you. Literature is not the easiest of subjects for everybody, and a number of people find it very hard indeed to read literature and identify things such as imagery, symbolism and themes. You are not alone!
But I do have good news! You have already posted this question on enotes, which is a site dedicated to helping students like yourself. Not only are there a large number of editors like myself who are passionate about both literature and helping students to understand it, but you also have access to a vast number of study guides on nearly every single text you will ever study in literature. I have included a few links below to the study guides of some Shakespeare plays so you can see what I am talking about.
So, my advice is use enotes as a resource to help you. Search for the study guides of the texts you are trying to understand or are confused about, and ask questions for people like me to answer so that we can use our knowledge to help you.