Format:
The Multiple Choice Question section of the AP Exam consists of 55 MCQs. These generally come with a stimulus source that the questions are answered with. This section is 40% of the exam grade, and lasts for 55 minutes.
Step-by-Step: (Disclaimer: Your teachers may have different recommended processes for answering MCQs, this is just what works for me)
Step 1 - Read the DESCRIPTION of the stimulus source to get general context on the time period and content of the source.
Step 2 - Read the questions.
Step 3 - Quickly read through the stimulus source, focusing on sections relevant to the questions.
Step 4 - Answer the question.
Additional Tips
Use process of elimination - 2 answers are blatantly wrong (wrong time period, doesn't answer question, etc.)
Sometimes, the stimulus materials are not necessary to answer the question. If an answer is obvious, go with it. This can save some time for you to review or go back to difficult questions!
Pace yourself - If you are struggling to answer a question, mark it for review and proceed with the next question. Don't waste time, since you are allotted 1 minute per question!