When analysing a source there are some easy rules to stick to in order to ensure a deep analysis. Firstly, never take what you're reading or, if it's a picture, looking at at face value. Every source has an agenda and it's your job to find that agenda. Think about when it was written, by whom and what it is about. Make sure you understand what the purpose of the source was as this can be very telling on what the author's/ illustrator's viewpoint is. Just because something is an eyewitness account doesn't necessarily mean that it is reliable, think about what the source is missing in its account and why it misses it. Through doing this you'll ensure that you're giving an in depth analysis.