Russian Strategies

Since Russia is the biggest nation in the game, it's also the country with the most opportunities to expand. Their larger land makes difficult to erase it, but also makes defense harder since the provinces are far apart from each other. On lower enemy games, Russia is quite easy. On higher enemy games, however, you'll have to multitask, fighting multiple enemies at once. China will likely try to take Kazakhstan if it isn't an enemy, as well as the Korean Peninsula and Japan. Also, if the US takes Alaska they can cut you off from Canada, and W. Europe may take over Fennoscandia (Norway, Sweden and Finland) and Eastern Europe, effectively cutting you off from most of the world. The best places to expand to are Europe and Asia, as they are close and there's plenty of territories to use for research and defense. Given its location, it may be difficult and nearly impossible to defend against multiple First Strikes, due to the proximity to many other superpowers, mainly China, W. Europe, Kazakhstan, India & Pakistan, Israel, Iran, Australia and USA.

Make lots of cruisers and always try your best to defend your land, expand fast and research only with provinces that are well protected, otherwise you may lose the territory along with its missile capacity, the research progress you made and time as you'll need to reoccupy the lost land. Prioritize defense and expand steadily, while picking off smaller and nearer enemies, like Iran, Kazakhstan and Israel. Beware of USA, China, India & Pakistan and Australia First Strikes since they have a lot of land and thus, lots of missiles.

An alternative, valid option is to avoid exchanging nukes with bigger nations and trying to stay neutral so you can spend most of your time researching, and after some nations are wiped out you can focus in attacking the debilitated survivors while expanding into nearby territories quite easily (it doesn't happen in Extreme Mode since enemies are far more likely to attack you anyways).