Many researchers will not create their own data but will re-using others' data in new and imaginative ways to carry out further research.
Here are some sources of data that you can re-use
UK Data Service/ UK Data Archive Service
Their primary aim is to provide users with seamless and flexible access to the UK’s largest collection of social, economic and population data resources. Please see Advice for new users. You need to register to use the service. hey have lots of different types of data available – see their website for further information.
Google Dataset Search
Google Dataset Search can help researchers locate online data that is freely available for use. It locates files and databases on the basis of how their owners have classified them. It does not read the content of the files themselves as search engines do for web pages. This means that metadata is extremely important in order for people to find datasets.
The UK DATA Service has a YouTube channel where they have lots of videos and webinars available, and they also offer guides on particular datasets, topics and methodologies and software. In addition, the Service provides a range of Data Skills Modules.