Russia is the largest nation on Earth, but its very underpopulated for the territory it holds. The European portion of Russia contains the highest concentrated population, if I'm not wrong, but the further eastward, the less populated Russia becomes. And I believe many of those that do inhabit Asian Russia are not ethnically Russian.
So the challenge is to increase population and population density in Russia. And, for bonus points, what would be the effect of a Russia with a higher population?