We, as architectural illustrators, have to see the world with an artist's eye. Often, I get questions, about how I create such realistic renderings. My reply is simply, use a lot of real world references and try to recreate it virtually. Our brain often plays tricks with our eyes. We tend to see what we want to see and not what reality is. Try this. Grab a photo of a snowy day (just an example) and using an image editor like Photoshop sample the color of the snow. You'll find that the snow isn't actually white at all, but our brian knows snow to be white, so it is overriding what we actually see.
Most of the time, when we look at the world, we aren’t actually looking at all. Instead, we are relying on the knowledge about the world we have stored up over years. We know the table is flat, so we don’t actually bother to observe how that flat rectangle on four sticks looks out there in the world from the particular position in which we are currently standing.
Our brains operate as efficiently as possible to filter the wealth of information coming through our senses. In fact, we don’t truly see with our eyes at all – we see with our brains. Only those things which are unusual, a potential threat, or have changed significantly, cause the brain to react – our attention is caught and for once we are genuinely looking at what is out there.
When we were children we looked at the world like this most of the time – everything was new to us – exciting and waiting for us to discover it. As we got older, less things were new. We’d already seen so many trees we stopped looking at bark patterns, the same happened with the clouds in the sky and on it went – as our body of knowledge grew ever larger we paid less and less attention to those things we had seen before’.
Fortunately it is possible to recapture that the ability to pay attention to the world again – and to look at things directly rather than filtered through a cloud of knowledge. Some knowledge is of course required for rendering, but make sure it’s the right knowledge. The laws of perspective, what something looks like from every angle – this is the kind of knowledge you need and will develop as you learn how to render.
One of the most crucial part of a photo-real architectural rendering is textures. In my snow example If, you make your snow white it will not be natural; it'll look off and your viewer will sense something is wrong. Try adding either a fresnel reflection or tinting your snow material blue, which is actually what is happening in real life.