Until fairly late in 2014, I, like most non-Russians, didn’t even know about the Tsesarevich title. All my reading about Russian history, and all the Russian literature I’d read, hadn’t yet enlightened me to this fact. However, now that I understand the difference between the titles Tsesarevich and Tsarevich, I haven’t misused them ever since.
In 1721, Peter the Great discontinued the title of Tsar in favour of Imperator, Emperor. Thus, the title of Tsarevich for the heir apparent or presumptive fell into disuse, as did the title Tsarevna (except for Tsar Ivan V’s daughters, one of whom became Empress Anna). From this point on, the Tsar’s daughters were titled Tsesarevna (later Grand Duchess, the Russian form of which actually translates as Grand Princess). Starting in 1773, Tsesarevna became the title for the wife of the Tsesarevich.
In 1762, upon the ascension of the pathetic Tsar Peter III to the throne, he created the title Tsesarevich for his son Pavel (the lovely woman-hater we can blame for having indirectly caused so much trouble in the monarchy at the end, thanks to his draconian, male-only inheritance laws no one had the guts to revise). In 1797, the title became law. The Tsarevich title, from then on out, merely referred to any son of a Tsar, not just the heir apparent or presumptive.
Most non-Russophiles innocently use the title Tsarevich and have no idea Tsesarevich even exists, but people in Imperial Russia certainly only referred to their heirs by the proper legal title, Tsesarevich. In the case of Aleksey, the last heir to the Russian throne, both titles are technically correct, since he was the only boy in the family, but no one in Russia ever called him Tsarevich.
Like Tsesarevich, the title Tsaritsa is largely unknown among non-Russophiles. For a long time, I too innocently used the more common title seen in the English-speaking world, Tsarina. However, this title isn’t just legally incorrect, like Tsarevich. It doesn’t even exist in Russian.
From 1721, the official titles for the Imperial couple were Imperator (Emperor) and Imperatritsa (Empress). Tsaritsa was never a legal title, but widely used informally and unofficially. It’s kind of a pet name for the Tsar’s wife. I prefer it to Empress, because it’s just more Russian.
I personally use letter-by-letter transliteration from Cyrillic, except in cases where exact transliteration looks awkward and weird. For example, Ukraine’s capital truly transliterates as Kyyiv, but I use the official transliteration preferred by the Ukrainian people, Kyiv. I also don’t render soft and hard signs with apostrophes, since even I think that’s nitpicky.
Different people have different transliteration styles, and I can live with a style that’s not my own so long as it’s consistent. However, some styles seem more old-fashioned than others, like “translating” certain names, or “translating” names of royalty. I understand certain people are much better known by Anglo names in the English-speaking world, like Peter the Great and Nicholas II, but it’s really arrogant and Anglocentric to use names like Serge, Elizabeth, Michael, Marie, and Eugene for people who were only ever called by Russian names.
Spellings like Aleksandr, Anastasiya, Mariya, Vasiliy, Tatyana, and Feliks only look strange and unfamiliar at first. Once you’re used to them, it seems strange to see the more old-fashioned transliterations.
For more details on my transliteration style, please see this post.