Dissertation requires lots of research. You have to be really focused on your task to complete your dissertations. Just like other kind of assignments, you cannot just use the literature review for your dissertations. But, you have to conduct your research right from scratch to collect all of the information you need to complete your dissertation. You can even get help from a professional Dissertation Help to write a professional dissertation for you. They are experts and know how to write the best one. You can use various methods to collect your data, like observations, interviews, and surveys. This will help you to collect your data directly from your sample.