>>3464346>see something that is visually pleasing
It's hard to really pinpoint it because of how vague "visually pleasing" is, but it's something interesting, maybe a weird coincidence of lines or angles, an old car, an interesting shadow, someone who looks out of place, or just some slice of life moment that everyone can relate to.>pick a rough focal length
Do I want to convey the vast distance between my subject and the surroundings and get everything in the shot by using a 20mm lens? Do I want it to look like it does to my eye with a 35-50ish mm lens? Do I want to flatten the subject a bit or make it seem small in comparison to something big behind it with a 70-100mm? Do I need to bring it a lot closer to me with a proper telephoto?>what else do I want in the frame besides whatever caught my eye
This is vague again, some peripheral subjects can compliment your main subject, you hear people talk about "negative space" a lot, that one is pretty easy. Or similar shapes, complimentary colours, landmarks to give size perspective, an environment from which your subject sticks out from, etc.>what do I NOT want in the frame
This is a hard one, you should remove everything that doesn't contribute to your composition. Distracting colours, unimportant objects that are only halfway in the frame and give you a feeling that the scene is awkwardly cut off, things that break the theme, etc. Use your feet to position yourself around your subject, use secondary subjects to hide distracting shit behind them, adjust your focal length, add more BOKEH, etc.>positioning everything
Just put your subject at the golden ratio (like a third of the way between one third and the middle of the frame, closer to the third) and don't put your secondary subjects too far out to the edge of the frame. Play around with putting the horizon at golden ratio, the middle of the frame, try to angle yourself in a way that shit like fences or poles form a line that leads to your subject, etc.