Struggles with Painter's Tape

I've had this idea to continue the accent stripe that's in the shower along the rest of the wall with paint.
So I trudged on over to Home Depot and picked up a quart of paint similar in color to my glass tile. I carefully laid out 2 level lines of painters tape and painted the stripe in. The color is great but I couldn't prevent the paint from the bleeding out a little past the tape, and when I took the tape off I peeled off some white paint in the process. Not sure how to prevent that.

Unfortunately, I can't claim credit for this brilliant idea. Credit goes to Sarah Richardson.