The literature review of a dissertation should include critical analysis. You cannot simply juxtapose the literature you find: you have to evaluate and draw conclusions from it.
Try expressing your voice in each paragraph of your literature review. Write strong paragraphs. In strong paragraphs your voice can be heard in the topic sentence, development (where you analyse and compare/contrast the sources, sometimes as individual pieces, sometimes in a synthesis) and, even more easily, in the concluding sentence, where you present the "therefore" of the paragraph.
How to express criticality at the paragraph level:
Identify the significance of the sources, and why the points they are making are relevant
Make connections between the sources
Compare and contrast sources, literatures
Accept/adopt points made by the sources, with reasons
Reject the points made by the sources, with reasons (e.g., limitations in the methodology; out of date; limited scope; geographical delimitation)
Indicate the position you are taking in your own work on the theories and concepts presented by the sources
Show how limitations in the existing literature create a research gap for you
Organise the materials, synthesising them in an original way, that sheds new light on the topic.
To find out more about paragraph writing, check out the Assignment Writing Guides.
Literature review level
Try to take ownership of the literature review. Remember the purposes of the review (providing background on the subject you are researching and identifying a gap in the existing literature on this subject). Thus, throughout the review:
Identify the key themes relevant to your subject matter
Identify the most logical and effective order for your themes
Relate the sources back to the dissertation's research question
Shed new light on the topic
Draw conclusions on the existing literature
Identify gaps in the literature
Your literature review should present an argument (which you can recap in the concluding paragraph of the literature review). For instance,
"The literature says/illustrates/reveals that... there are debates in the literature as of... it can be understood from the literature that... however, there are gaps in the literature... the literature does not specifically address (specific sector/location/population)... there is a lack of independent/recent studies on... therefore in order to answer the research question(s) (you can repeat the question) this dissertation uses method xyz, as illustrated in the next section (if applicable)".
Manchester University’s academic phrase bank is a great resource for learning new words and phrases.