I hardly ever use masking fluid. (Though I will sometimes, if I think of it, use a wax crayon, which isn't removable.) Probably I don't use it stategically, but to me it is always too obvious.
I saw someone use a masking pen online and got myself one to try.
It goes on easy, very controllable, but is nearly impossible to remove! I gave up; where I was able to remove it, the paper is damaged.
(I wanted to take a picture of the pen, but I think the cats must have batted it under something!)
Back to no masking fluid.