Summarise the texts that you read and group ideas into themes as you go, not forgetting to reference very carefully.
It is much easier to take irrelevant text and references out later than to add them in and remember where the ideas came from.
Then start to read around those subjects to narrow down the field of interest.
Now is a good time to identify a possible supervisor and talk to them about whether they would be prepared to supervise you and help you narrow down your research topic.
The first step in any research is to identify the topic of interest.
Think about which areas have most interested you in your studies to date, and what you would most like to explore.
As a general principle, it is better to research a narrow topic in more detail than a broad one in very little detail.
Start to write up your research proposal as you read around your subject.
Whether or not you are required to submit a research proposal before your dissertation, it is good practice to summarise what you plan to do, and why, before you start as it will help to keep your research on track.
A research proposal is a document in which you outline the case for undertaking the research project, your dissertation or thesis, and present your plans for carrying out the work.