I painted my way through college and then some. I still enjoy painting, it's the prep and cleanup that can suck. It's the prep and cleanup that make a job look good or bad, too.
I don't mask edges to create a hard edge unless it's in the middle of a flat wall and has to be perfectly straight. At edges of adjoining materials, where corners meet, on windows and doors, etc. I cut in by hand with a good brush. A high quality angle brush helps as does a very steady hand. I have both and was taught by old timers that chose painting as a vocation and a career. Tape is for putzes and it adds time to a project. It also leaks or weeps too often to rely on.
If you're going to tape plan on pulling the tape as soon as you can- preferably while the paint is still supple, before it's fully cured. Then you shouldn't get runs, tear offs, and smears. Also, buy the good tape with the modern adhesives, not the cheap stuff and not old stuff that's dried out.
Masking is great for spray jobs, but only to protect other surfaces from getting painted. It's still wise to plan on some cutting in.
A trick for windows is cut in by hand and allow your brush to lap onto the glass just slightly- it helps seal the joint, too. Go as soon as the paint is set with a safety razor and scrape the glass- it will leave a flawless straight, smooth edge.
Roller tip #1: Never push on the roller to force paint out. Always dip your roller and keep it full enough that you don't have to press hard. It's easier to do, does not leave streaks, and provide uniform mil thickness.
Roller tip #2: use a heavier nap on the roller than you usually do to get heavier coverage and a slight texture from the paint.