So I've been trying to pre-visualise & compose photos in manual mode, and I must say it will take me quite a while before I am able to casually get a correct exposure out of any given situation. At my current level, it takes some trial & error before I get it right. I start guessing the ISO, then I set my Aperture & Shutter Speed (not too familiar with white balance, so I leave it to auto). From there, I shoot & correct the ISO as necessary.

Not sure if this is the correct way to do it, but I guess time & experience will reduce my trial & error method. Ultimately, I'd like to be able to judge something on the go, and be able to get it right the first or second time.

Am I doing this right?

I've recently found the aperture mode to be quite fun to use, I just need to increase the ISO if the shutter speed gets too slow. And its quite useful when you need to shoot fast. I am just curious about your thought processes before you press the button.