For example, if I wanted to say "I'm really rusty at chess because I have not played it in a long time", how would I do so while sounding more or less casual? I could say something like "Я совсем забыл как играть в шахматы", but that feels a bit unnatural and seems to imply that you've forgotten the rules of chess, rather than that you're simply out of practice.

This is even harder to translate when talking about video games, for example "My aim in CS:GO is terrible, I'm so out of practice". "Я совсем забыл как целится в CS:GO, ведь я так долго не тренировался" seems a bit convoluted, and I have no idea how to properly translate "aim" :/

For example, if I wanted to say "I'm really rusty at chess because I have not played it in a long time", how would I do so while sounding more or less casual? I could say something like "Я совсем забыл, как играть в шахматы", but that feels a bit unnatural and seems to imply that you've forgotten the rules of chess, rather than that you're simply out of practice.

This is even harder to translate when talking about video games, for example "My aim in CS:GO is terrible, I'm so out of practice". "Я совсем забыл, как целиться в CS:GO, ведь я так долго не тренировался" seems a bit convoluted, and I have no idea how to properly translate "aim" :/