When I read draft REF outputs, the most common problem is not weak research. It is that the paper waits until the Discussion section to say why the work matters. Assessors work through hundreds of outputs, and a paper that does not show its originality, significance and rigour early makes that judgement harder than it needs to be.
One point worth settling before you start. Significance in an output means the contribution to knowledge. It is not the reach and significance of an impact case study. Different element, different test, and the two get mixed up.
Here is one thing to try this week. Take a paper that might go forward for REF 2029 and underline the sentence in the abstract that says what is new and why it matters. If you cannot find one, write it: what did we not know before this paper, and who is that a problem for? Then move that sentence into the first two lines.
It takes ten minutes, and it is the change I see make the biggest difference to how a paper reads to someone outside its niche.
Mark (Prof. Mark Reed)