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)

What are you trying to accomplish by adding these (seemingly fictional?) roadways? You seem to understand that they are not appropriate for OSM.

Welcome to OSM. Can you describe what was incorrect about the crossing that you removed?

Welcome to OSM, and thanks for your contribution. Please don't use descriptive names like "Home" and "Driveway" - it's totally fine for objects to not have a name. I have fixed this for you. Happy mapping!

I reverted this edit because it looks like you replaced an entirely different business with your own. Please do the built-in tutorial and try again

changeset/166186011

Welcome to OSM, and thanks for your contribution. I removed the descriptive name and tagged it as a driveway based on aerial imagery.

I also added the address to the front building abutting the driveway. If there is additional unit information you are welcome to add it as well.

Welcome to OSM, and thanks for your contribution. Both of your edits look good to me.

reverted

changeset/166045686

Welcome to OSM, and thanks for your contribution!

Google maps is sadly not allowed to be used to contribute to OSM. If you know this from visiting in person, that's sufficient.