Look, we're not going to lie. There's a reason War and Peace has become the byword for extremely-long-and-difficult-work-of-fiction. Think of it as stair runs for your brain – there's definitely some major pain involved, but it's worth it. What kind of pain specifically?
1. It happens long ago and far away. So you have to deal with the fact that we're talking about stuff 200 years in the past, when morals were way stricter on the sex but way more lax on the owning-people. And you have to keep in mind that we're in another country, with a totally different political and economic structure and unfamiliar place names. And speaking of names...
2. The names. The names! OK, a quick mini-lesson on the Russian language. In Russian, you can transform words by adding endings to them. For names, this means that any kind of endearments are created by taking the normal version of someone's name (say, Nikolai) and adding some cutesy-poo suffix (Nikolushka). Even more confusing is that you can have several kinds of suffixes that all pretty much mean the same thing but make the name look way different (Nikolenka, Nikolaichik, Nikolusha).
So that's one thing. Another thing is that in the 19th century, Russian aristocrats mostly spoke French to each other, so their Russian names would get translated into a French version (Nikolai to Nicholas, Natasha to Natalie, Pyotr to Pierre).
A third thing is that the polite way to address a stranger in Russian isn't by using her (or his) last name (like in English we say "Ms. Smith"), but instead using her full first name and her patronymic, which is a fancy middle name derived from your father's first name and means daughter-of-so-and-so or son-of-so-and-so. (So Natasha would be called Natalia Ilynichna, because her dad's name is Ilya.)
And finally, Russian nouns have different endings depending on whether a word is masculine or feminine. So even though Natasha and Nikolai have the same dad, Natasha's full name is Natalia Ilynichna, but her brother's full name would be Nikolai Ilyich. Whew. Many editions try to go easy on the name thing to spare readers the confusion, but not all – so just be prepared. We went with Pevear and Volokhonsky's translation.
3. The narrator goes off-topic. Don't expect to constantly be reading about the characters. A lot of the book is long essays by the narrator about the meaning of power, the relationship between those in power and those who take orders, what causes events to happen versus how history explains events happening, and so on and so forth. These essays and digressions are really, really rich and deep, but they can sometimes be a bit of a slog. Fair warning.