In article content, use the correct diacritics at least the first time the name is given.
When linking to destinations, the local script is unnecessary clutter. That is, the Tokyo article is linked to as "Tokyo", not "Tokyo (東京)"; if somebody wants or needs to know the script and reading, it's just a click away.
Chinese romanization is complicated by the vast variety of dialects used and some intractable political difficulties. Rules of thumb are:
For articles about mainland China, use Hanyu pinyin romanization and simplified form Chinese characters.
For articles about Hong Kong and Macau, use Cantonese with Yale romanization and traditional Chinese characters. However, if the most commonly used name is under a different system, use that and not Yale.
For articles about Taiwan, use Wade-Giles romanization (without the necessary apostrophes) for older and well-known place names and either Hanyu pinyin or Tongyong pinyin for lesser known placenames (depending on which political party is controlling the locality, but we won't delve into that mess here). The Chinese characters included should be in traditional format.
Use tone marks, not tone numbers. Use the tone converter if necessary. If you don't know the tones, leave them out and somebody will add them later.
中国 is Zhōngguó, not Zhong1 Guo2
Use space between words, not between every syllable. Don't capitalize each syllable.
南大街 is Nándàjiē (South-Great-Street), not Nan Da Jie or NanDaJie
天河北路 is Tiānhé Běilù (Heaven-Lake North-Road)
Do not use tone marks for article titles, but give them in the intro.
Shanghai (上海 Shànghǎi) is a city.
Place parentheses around Chinese characters and their pinyin readings. Do not use bold or quote marks.
Hebrew romanization is highly nonstandard and complicated by the existence of numerous dialects with varying pronunciations. The closest to an official standard is the United Nations romanization (ISO 259), which is particularly useful for the traveller as it is widely used in maps and signage.
For Japanese, Hepburn (written by an American for foreigners) has been the de facto standard of romanization for the past 100 years especially in publications geared to foreigners, while official standard Kunrei (written by Japanese for Japanese) is used very little. Thus: