How does one overcome Russia?
There are two ways. First way is to do what the poster says above me in his spoiler.
The second way is to max out your turns to accumulate cash , build up your troops for 11 of your best girls and your self you have to conquer every other nation available( you get special items for conquering the harder nations first of course everyone else upgrades too but those items are very useful when given to the right characters) besides the EU and take 3 turns after every action so you are only using one action per turn this works only when you are in between campaigns and are working on side quest which will also help your girls get better skills and also increases your items for boosting stats. While in campaigns you have to play to win so skipping actions will not work out most of the time there are a few spots you can do it though just save often so if you get clobbered you don't lose to much time. If your troops are strong enough early on let the side quests accumulate as you take city's your daily income goes up once you need to increase your troops to win then do your side quest to get the cash you need. Make sure after every side quest you skip 3 turns if you skip a 4th turn you will have to fight. You can use those(4th skip) fights to boost troops but you will also lose troops sometimes and that will cost you gold...
You need to get all 11 girls and yourself to 7k troop levels once you are in a fight you lose half of your troops due to the cold weather penalty, make sure you save enough cash to fully re=gen your troops after each battle. Now this is key you only fight one city at a time so use one action and end the turn when they counter attack you can use your other troops because during counter attacks you don't lose any troops from the cold. You can actually do this with just 6 at 7k troops but even during counter attacks they are pretty strong so I will sometimes use the other 6 to defeat the counter attack. plus having 12 total at 7K will give you flexibility for strategy purposes sometimes you need archers sometimes you need brawlers.... Also when you get to Moscow you have to defeat defenses and then the main fight. you can end your turn after defeating the defenses or you can be brave and try to win it with your remaining 6 troops that are at 7k. Obviously you can do this easier with more than 7K but you will spend so much gold getting them there that the rest of your girls will be so weak that you will never catch them up and it will cost you later on. I have all the rest of the cast around 5K each except for a few which to me seem worthless.
There are some nations that counter attack many times so use the minimum of troops for each battle I pretty much do something that is counter intuitive I will use the weakest charterers when ever possible and save at least 4 really strong ones for certain nations counter attacks , India is one of these places and also Egypt there are a few other nations that will surprise you as well with the number of times they counter attack ,so always keep some guys for counter attacks. Oh and when fighting in Russia always equip your team with a healer and use them to heal every turn they have because you can boost you troop level back to full during combat this will save you gold when it comes time to re-gen..
There are several other ways to deal with what I said above but this way works good and as I said makes it easier to get all your other girls troop levels built up after you defeat all the nations you can get bonus items from. You did it right if your turn count is really high. You can do this on your first playthrough. Second play through you can elect to keep your items and go for the lowest turn count.
Some will say this method is not cool but it can be done. when playing the Gold version you can get achievments for low turn counts , suggest looking in the first 40 pages of that thread there was a user there that explains how to beat the game in under 100 turns I tried it and it works but is really challenging.