My recommendation to using all Peter has to offer:
1) Play peacefully early, but try to build 6-8 cities if possible. If you get cramped in, then take out one neighbour with an early war (axes or axes/swords or archers/cats or eles/cats).
2) Once you have 6-8 cities then run max scientists (get the GL) to get to liberalism asap (get metalcasting, calendar and compass but NOT machinery to lightbulb liberalism directly). If you have competitors take nationalism. If you don't, research nationalism and gunpowder and take military tradition.
3) Use cossacks to expand your empire to 15-20 cities (15 is sufficient but try not to leave an enemy around to smolder).
4) Cossacks though aren't the super-power they used to be and besides if you go for domination you don't get to see the power of the Russian UB. Instead, my vote would be to transition to full-fledged CE under CE civics with 1 gpfarm and a handful of state-property production centers. Beeline computers immediately following democracy and communism (try to get both wonders there). 2 free scientists across 15 cities is 30*3 beakers*modifiers. That's a boatload of free science
5) Endgame: Once research institutes are online in all your cities (they should be rushbought, you got kremlin didn't you?

) then you should superpower research your way to industrialism (for aluminum) then rocketry (start apollo) then robotics/satellites (start space elevator) and fusion (use GE on space elevator). Then go for the win.
Final point: Expansive is really nice with CE because it lets you get to size 20 to work all those cottages a lot sooner. With hereditary rule early-to-mid game and all the

bonuses late game health is your only limitation, but not so much with an expansive leader. So, again, I think that domination would foreclose on this bonus although there is still some synergy with large cities and domination wins of course.