When answering source based questions it is incredibly important to devote at least 10-15 minutes on analysing the source itself, this will help you plan and structure your answer more effectively. You should always try and immediately identify 'the big message' of the source and make sure that you place this in your introduction so the examiner is aware that you have understood what the source is trying to say. The second most important element of source based essays is linking the source to your own knowledge, however it is important to only include knowledge that is relevant as you will not get marks for demonstrating your own knowledge if it bears no relevance to the source at hand. Your own knowledge should be used as context for analysing the source. Another key factor to consider is provenance, that is where the source came from, who wrote/created the source and when it was published. Although provenance is incredibly important you should avoid using words like "bias" when discussing the source and instead discuss the source's provenance in relation to your own contextual knowledge. For example if you have a European source dated July 1914 you should immediately identify the date as being during the July Crisis and discuss this in relation to your answer. When writing about multiple sources you should avoid structuring your essay in a way that discusses the sources individually and instead attempt to structure your essay thematically. Doing this will ensure that you write about the sources in relation to each other and draw links and comparisons between them, which is what the examiner is looking for.