I have taken AP World History and AP US History. These are some of my study skills that have really helped me excel. These may or may not work for you.
Notetaking: Make your notes colorful and fun to read! Uses different colored pens and draw doodles (that relate to the topic) if you want. A big portion of history classes is memorizing the historical information and a great way to do that is to read over your notes. Additionally, it is important to not write too many pages of notes with unnecessary information. For reference, I usually write 1 page front and back for a 30 page chapter. My teacher gives us a vocabulary list of words and essential questions of the chapter and I focus my notes around that. Examples of notes:
Historical Thinking Skills: This is probably the biggest thing that has helped me in AP history classes. For every unit, I would make compare and contrast charts, look at continuities and changes throughout the era, make a timeline, and write down the cause and effects of events. Once you do this, it will help you understand the content much more deeply. This helped the most in my essay writing and short answer questions. Here are some examples.
Work in a group: This tip is pretty self explanatory, but it is so helpful to work in a group. I find that I work better in groups than I do alone. Just make sure to choose a group of people who will not get off-topic and who are focused.
Read, write, and hear the information as much as possible: For me, the best way to memorize information is to see, write down, and listen to the content as much as possible. Watch review videos on YouTube, read review books actively (Princeton is a great one), make flashcards for the vocabulary, etc.