I mean like in my case, if we can't get a data, we generally propose theoretical frame work and may use other's data with proper referencing to put new theory. You can validate your new theory by using data of others and can show how your method is much better.
See, I had to work on simulations and solving too many mathematical equations, but in the mean time I read few research papers and find that I can give a better approach, I tell my prof. that this is the problem, I am working on this subject but it will take time due non-availability of lab or anything, he can guide you on another topic calling it secondary work .
Another way is collaborating with other student, just one partner, so that you can get publication number increased.
Like two juniors used to work with me, I focused on one project with all the work, while with them we used to divide the work as all have similar field. He may not solve or simulate one thing, so its better to cut the time and work together. This helps in a way that you become a co-author.
So, I will get my own publication for my work which will go in my thesis, but they will also get their publication which will go in their thesis but since I also worked in it, my name as co-author will be there. So in my CV I have 1 paper as main author and 2 as co-author.
Dedicated to Krait, Talon. 
