Use the meniscus to find the eye-level line, horizon line.

When looking at a landscape or urban setting defining where the eye-level line is can be tricky. Sure, just look straight ahead and you have it, but experience taught me that it is too easy to look a little bit up or down but not actually level. So here is an old trick.

Use a glass with liquid, wine works perfectly, but for this I will use a glass of water. If you remember your high school chemistry you learned to look at a measuring beaker and find the liquid level where it forms a straight line, nothing above or below. That means that you are looking straight across the liquid, at eye-level.

Here is the scene I was looking at:

Here is a glass of water with the meniscus line:

So looking at the meniscus line I can create the eye-level line for my scene.

Once you have the line, pick a point in the scene to reference as you sketch, maybe the red awning.

Then you can apply the principles from a blog I did a few weeks ago about perspective.

I hope this helps, and of course let me know if you have questions.