It's cool to see some of your new stuff. Here is some feedback for your 2 latest pieces of work:
NY Street 1940's:
You've gathered some great elements to build the final piece (vehicles, signs, buildings...) and that's a very important step in my opinion.
But I think you need to put an extra effort on things like perspective, black levels, atmosphere... In this piece, I think perspective is suffering the most, specially if you compare the strong vanishing point of the street against the flat buildings in the BG.
Perspective can be the most tricky/important aspect of an illustration. Sometimes, using a 3D software to do a very quick layout will help you to avoid perspective mistakes.
I would recommend, when gathering several photo elements, try to keep a consistent focal length, I think is quite simple to access to this metadata using photo management softwares. Also those BG buildings could use a bit more of definition and separation between each other. Try to create more accurate masks for your images, I can see glowing edges in some of the MG buildings.
Maybe, try to be a bit more gradual with the overall atmosphere, right now it feels there is only 2 levels of haze, the one in the BG being 100% and the FG being 0%. i.e. check how contrast the police car is, very deep blacks and super shiny whites. It should be affected by the atmosphere a little bit as well as the rest of the elements in that MG area.
Work a bit on the integration of the cars, specially the ones at the right side. The one in front of the cop car is missing its contact shadows therefore seems to be floating. The FG truck feels a bit better but a stronger contact shadow around the tires wouldn’t hurt. Also, this elements gives you a great chance to study its materials: see how bright that chrome rim is. Since it is a very reflective object, it would probably would look more integrated if you apply some colors of the blue ground and the red buildings. After all, chrome looks the way it looks because it is reflecting the environment.
The red building on the left side has a strange texture pattern, looks a bit too regular and repetitive, almost like a small texture being tiled. The windows seem to be the same element. Adding a bit of variation will make it look much more natural.
The scene feels a bit static. The cars can help adding a bit of motion to your image, but there are other elements you could add to give more life: maybe you can add some steam coming through the sewers, having some leaves from trees on the ground or flowing in the air, same thing with newspapers or flyers, or even having some character.
In your previous image, the one with the old town, I think you have achieved a nice look. I am just not sure about the left side of the image in terms of composition. It feels like you could extend your canvas on the left side by 1/3rd, reveal the cathedral in the BG and maybe add an extra row of buildings to close your composition there. The blacks are way too dark in the MG and BG, there is no atmosphere and everything in the picture has the same level of contrast, however, I think the layout and placement of the buildings and elements is quite nice, it is just the lack of atmosphere what’s affecting your piece in a negative way.
And finally, I think your backlit sky is not really matching the lighting that you have set, based on the hero building which is being lit almost 45 degrees front. I think it is a beautiful sky actually, so here you would have to make the decision of changing your sky for one that matches the lighting of your buildings, or try and change the entire lighting of your buildings to match that pretty sky. I would personally try the second option, since it would give you a great chance to create a very cool mood, as backlit scenes tend to enhance the atmosphere.
Please, have a look to the attached images to see what I mean.Using a backlit setup would darken all the facades of the building as the light would probably only reaching the rooftops, creating a very cool contrast of little highlights and shadows. Also, since the light source is very low, you could create a nice dawn/dusk setup, with strong color contrast between warm highlights and cool shadows, and of course, lots of atmosphere! Plus, it will give you the chance to add some artificial illumination like some interior lights in the buildings or the lightposts…
Anyway, looks like you have a big passion on creating images and illustrations and I hope this feedback can help you somehow, so keep putting all the effort you have been doing so far :)