I agree with much of what has already been said. The two big issues are that the lighting of the cutouts don't match the space and the busyness of the images. The lighting issues are common, but can easily be remedied by first finding companies which offer multiple lighting options, such as direct and flat lighting. You will still need to do some touch-ups, but it makes a drastic difference. For the amount of people you place, in addition to what has been said, remember the focus should never be the people. For each of your images, there is a person who captures my attention first and the space is secondary. Part of that is because they're brighter, but also because they're centered. Take your second image for an example, I'm immediately drawn to the white shirt. If he is removed, my focus may be on the space more. Larissa provided great insights on shadows, which is also crucial. Lastly, I think one issue that hasn't yet been addressed is the camera angle of the space. Using your second image again for an example, there is far too much foreground that the image seems to ask for a lot of people. Is the rendering itself supposed to focus on the stores or the open space? If it's the former, you should bring the storefronts closer. If it's the latter, you could adjust the image to give the impression you're walking out into the open space from a store. This can provide an interesting perspective, but also limit the number of people you need to include.