https://twitter.com/RM_Transit/status/1784219694200737890
Sometimes I'll hear people in Toronto talk pejoratively about all of the development that's been happening at Yonge & Eglinton (in midtown). They'll say it's too much density.
But then you come across charts like the ones above (source previously shared here) and you realize that this location is the only section along the new Eglinton Crosstown LRT line that is actually starting to have enough people.
Based on 2021 Census data, there were about 40k people within 800m of the future Eglinton and Mount Pleasant stations. In contrast, there are many downtown stations along the Ontario Line (also under construction) with around 80k people.
Why this is important is because if the objective is to get people to ride this new transit and collect a lot of fares, then the single most important factor is going to be the amount of people that live, work, and play adjacent to each station.
Now, I'm not a transportation planner, but in my mind there are three simple ways to think and go about optimizing for this:
You can look at where population densities are already high and then add new transit to service these densities. This is what is happening with the Ontario Line and it was long overdue. We know that ridership is going to be relatively high because of the chart at the top of this post.
You can look at where there's existing transit and then work to optimize the land uses around it. This is what we should be doing a better job of along the Bloor-Danforth line, where certain station areas have actually lost people over the last few decades. This is the opposite of what you want next to transit investments.
Lastly, you can also proactively plan new transit while simultaneously encouraging more density. An example of this would be the Vaughan Metropolitan Centre (just north of Toronto). Extend the line and encourage growth. This is good. The only thing with this approach is that it can seem a bit misaligned if you're currently failing at #1 and #2.

Reece Martin is a foremost public transit critic based in Toronto. His YouTube channel, RM Transit, has over 284k subscribers and some 50 millions views. If you're interested in public transit around the world, he is a great person to follow.
He also writes a blog. And today, he published a post talking about the "5 places in Toronto that should have more density." This, as we have talked about many times before, is essential. The way you get the most out of transit is to pair it with the right surrounding land uses. And here in Toronto, we have many instances of "not enough density next to transit."
For instance, the first place on his list is Bloor-Dundas West:
The site already has streetcar serving on two routes, the subway, GO, and UP Express (which will be connected with the subway in the next few years — construction is underway), and lots more transit could show up in the future, from an extension of one of the streetcar routes to the Junction (with a transferway please), to the Ontario Line that will be primed for a second phase in this direction if development justifies it, to the potential for future Milton line train service. The site is arguably already the second-best served for transit in the country after Union, and could be made much better in short order.
Hang on this last sentence for a second: the second-best transit node in the country. That's an incredible asset! Now consider the area's land use plan (red is mixed use and yellow is low-rise neighborhood in Toronto's Official Plan):

Other than the mixed-use triangle wedged between Dundas West and the rail corridor, the area looks pretty similar to much of Bloor Street in this city: mixed-use along the major streets and low-rise neighborhoods everywhere else.
We know why this is the case; it is about maintaining the status quo. But it is a suboptimal way in which to try and create transit-oriented communities. We need more density, and we need to start thinking radially instead of linearly. So here's what a 500m walking radius looks like around Bloor-Dundas West and its two closest subway station neighbors:

The important thing to pay attention to in this diagram is all of the yellow that falls within each radius. This is land that ought to be zoned mixed-use, but that we have instead decided to make low-rise and single-use. If our objective is to create more walkable, sustainable, and vibrant transit-oriented communities, this is not the way.