Welcome to OSM, and thanks for your contribution. Please don't add descriptive names like "private property" or "(private)" - using access tags like you did is sufficient. I have fixed this for you, happy mapping!

You randomly dragged a bunch of nodes around in this edit. reverted

changeset/166998241

Welcome to OSM, and thanks for your contribution. On OSM, we try to make only one object for each feature ( osm.wiki/One_feature,_one_OSM_element )

I cleaned this up a bit to try to clarify where the actual venue is. In a day or so, you can use the routing tool on this website to test and make sure it routes people as expected.

Welcome to OSM, and thanks for your contributions. you also removed the brand and shop=supermarket tags from the Kroger next door - was that intentional?

Welcome to OSM, and thanks for your contribution. In general we try to "keep the history" by modifying existing objects instead of deleting and recreating new ones, even if the old one is substantially incorrect. I brought back the old node and combined it with the new information you added on yours. Please take a moment to make sure it's all correct :)

Hello, I reverted this changeset because you dragged two roadways very far. Please be more careful!

changeset/166806849

reverted

changeset/166759521

Please square your buildings (keybind is Q by default)
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Published using OSMCha: https://osmcha.org/changesets/166646408

Welcome to OSM, and thanks for your contribution!

You should only mark the part behind the gate as private - otherwise parts of the public road network, like the turnaround at Colina Trail, are not routable. You can do this by making a node at the gate and splitting the way there.

I fixed this case for you, happy mapping!

to add a proposed park you should tag it as
leisure=proposed
proposed=park
proposed=*#How_to_tag_in_general

I have fixed that for you. Happy mapping!

Also please make sure to connect the trails to other routable features, a lot of your trails end right before (but don't connect to) the San Gabriel trail

Hello,

you drew this on top of an existing trail drawn by another user. If you are using JOSM, please make sure to download everything in the area first so you don't accidentally do this

Welcome to OSM, and thanks for your contribution.

You deleted building=yes + leisure=fitness_centre tags - these indicate the type of feature this is. I went ahead and fixed that for you. Otherwise this edit looks good!

Happy mapping!

The location of the unit number is not possible to control. In some cases it may go on the next line because there is not enough room to render them side by side. A question, though - are these really unit numbers, or are they just lot numbers that the developer assigned? Unit numbers are part of the official address.

Welcome to OSM, and thanks for your contribution. You dragged around a couple highways in this edit and tagged the entire strip mall as the church. I have fixed this for you, and I encourage you to do the built-in tutorial in the editor before making any more edits.

Happy mapping!

you deleted some pretty big buildings in this changeset.

You could try https://umap.openstreetmap.fr/ (web based) or qgis (desktop app) for adding the parcels on top of OSM data. I'm not sure what you mean by your second question.

In general, OSM does not import individual plots like this. See this warning on the wiki:
place=plot

If you could explain what you are trying to accomplish, maybe I could help you find a better way to do it?

In general we don't normally add plots to OSM. You can map these as a node with only addr:* tags (name is not necessary)