how to paint a perfect line

I wanted to paint my boring stair case.  It is the focal point of my foyer and it needed something special.  It has carpet with an oak banister and spindles, blah...blah.. blah..  I wanted hardwood floors, but that is not happening anytime soon. 

before-

I decided to give it a facelift.  I painted the spindles with white gloss oil paint. Why oil paint?  I wanted it to last.  I first primed with an oil paint of course!  Remember I have 3 kids, and there is no way I am doing this again.

after-

I thought why not step it up a notch and make it more interesting.  And after I saw How to Paint the Perfect Line turtorial by Ask Anna, I did it in a couple of hours!