Decorating and Design - wall decoration

I want to paint an illusion of a lattice on a wall, approx.
5ft by4ft

Layout will be the biggest challenge. You will need to measure and mark lightly with pencil. Since it will be an illusion, you might not want to tape to make perfectly straight lines. Too, you might want to use a stencil brush and lightly dab paint to create a less than perfect look. A finer brush with a slightly off-color from the color of the lattice and painted with a free hand to highlight edges of lattice might create the desired effect. Practice on sheets of cardboard or posterboard until you achieve the look you desire. Or, you might want to get a piece of lattice and use it as a pattern to trace out the lattice work and take it from there.

I have seen lattice used as you would use a stencil , painting/spraying over it leaving the look of lattice on the wall, Though it would actually be the negative effect, it looks quite good.