What is your best paint edging idea?

Tape is the best edge. I like to use a large flat putty knife when I'm painting. It is not perfect but I'm too lazy to tape off the whole ceiling. The thing to do with something like a putty knife is to keep wiping the blade edge off on the side you aren't painting.

Simple,easy, lower cost https://www.youtube.com/watch?v=0cropa5reFk

I use one of these edger tools, https://amzn.to/2EMqAYY they work really well! Just keep the little wheels clean and free of paint!

I use an angled brush and cut it with a steady hand. It's so much faster than tape. If you make a mistake, touch it up with the other paint.

An edger and taping off the ceiling (where the ceiling meets the wall) should help. I like Frogtape, since it’s wider than the blue painters tape.

There are some good tips here:

https://m.youtube.com/watch?v=iv54RkauOiU

This is a way to use white caulk to get a straight line between a painted wall and a white ceiling. I plan to use this method in my bathroom - it was difficult for me to get a straight line over the tub. http://makelyhome.com/how-to-paint-a-perfect-ceiling-line/