@12before34 Uhmmm okay, here's an example. Last year I made this illustration of a haunted library.
I started with a freehand quick sketch. I usually have an idea how I want it to look so I do this first, because it's very important to understand that you have to decide where you place your horizon and vanishing points depending on what angle YOU want. Not placing random points then being a slave to them to the end! That's why I use my freehand sketch to help me determine where to place my horizon and points to obtain the exact angle that I want.
1.jpg
From there, I placed my horizon line and vanishing points. I place my VP in my mind, but you can physically place yours. If you draw traditionally it will often involve taping some additional pieces of paper to your drawing to draw vanishing points outside he frame. From there, I suggest you use your vanishing points to draw some guides on your picture (then you can remove your vanishing points because you won't need them anymore with the guides to help you). The guides look like this when I'm done:
2.jpg
From there I draw my final sketch on top with the correct perspective. It's similar to my freehand because I'm good at eyeballing perspective, but sometimes there's a more drastic difference at this stage:
3.jpg
Final
4.jpg
There you go, that's my complete process.
