I would suggest using JOSM to make the relations instead of iD, since with JOSM you can download all of the railway elements in HK with the built-in overpass turbo search and select large numbers of objects more easily.

Rather than adding the Wikidata tag to every child relation, I think it would be preferable to create separate relations with route=railway ("These relations gather rail infrastructure (track) elements"). This would also avoid highlighting all the platform outlines (although I'm not entirely sure if those relations are supposed to contain just tracks or all of the infrastructure).

Hi, welcome to OpenStreetMap. If something isn't actually signposted as having a real name, then you shouldn't add an unofficial descriptive name (never add names you made up yourself). I find it unlikely that a playground in HK would be officially called a "kid playground" in English (rather than, say, a "children's playground" or just a "playground"). You should add names in both Chinese and English in Hong Kong, per tagging convention (see the OpenStreetMap Wiki).

Hi, please don't trace from HK government maps, since they are copyrighted. It's better (and less legally tenuous) to use satellite imagery, although in this case your best option is probably to make an informed guess.

Hi and welcome to OpenStreetMap. (I've fixed your addition since you tagged the object as a motorway instead of as a building.)

Welcome to OpenStreetMap. Please don't add roads over existing roads; if you think the tagging of a road is incorrect and should be changed, just change the tag on the existing object. Also, please don't connect buildings to adjacent roads. The iD editor might do this automatically (especially where data is denser), so be careful about this.

Welcome to OpenStreetMap. Please don't add name labels like "House"/"hOUSE" unless objects are actually signposted or named as such.

Furthermore, it helps to be reasonably accurate when tracing roads and other objects from imagery, where the imagery is sufficiently detailed. Otherwise a volunteer editor is probably going to have to spend their own free time cleaning up after you.

…Welcome to OSM. Are you sure this dirt track in rural Tanzania is a secondary road called "poopy road"? Please don't add junk data and false information to the map, especially since many people, humanitarian organizations and companies rely on OpenStreetMap.

Welcome to OpenStreetMap. Unfortunately I will have to revert your changeset because you appear to have added fictitious objects to the map; please be mindful that OSM is a live dataset. If you think this is incorrect, please let me know.

Tagging convention for Mainland China is to only include the Chinese label in name=*; not sure why you added the English name as well.

此外，十號幹線的尽头是在桥上，不是在口岸里面。

深港西部通道是香港的路，就应该用繁体中文和英文的名字在name。而且真的名字（香港政府的）不是”深圳湾公路大桥“。=* (http://hk.centamap.com/gc/centamaplocation.aspx?sx=814955&sy=835385&z=5)

Hi. I've changed your tagging since the wiki page (osm.wiki/Asia/Asian_Highway_Network) says AH routes should use int_ref=* and not ref=*. I have sent an email to the OSM-talk mailing list (https://lists.openstreetmap.org/listinfo/talk) about the Hong Kong routes because I can't find anything outside the English Wikipedia and its mirrors which says that AH368 and AH374 actually exist; the articles don't have any sources and were created by a user who is now blocked for abusing multiple accounts.

China uses different tagging to Hong Kong; only the Chinese name should be in the main "name" tag and "Fugang Road" should be in the "name:en" tag.

Hi, welcome to OSM. Swimming pools should be tagged as "leisure=swimming_pool" (you've tagged this one as "natural=water" and "water=pool").

I've reverted this changeset because it was not constructive

I've reverted this changeset because it was not constructive

I'm not sure if it and Hong Kong station (no fare gates) should share a public_transport=station relation.

Central is one station, and as far as I'm aware should only have one relation for all four of the MTR platforms.