Lay the mirror face down on a secure surface that is at least as large as the mirror frame. Set the support rods a couple of inches from either edge of the mirror and just shy of the top edge.
Attach the support rods to the back of the mirror with a single screw placed at the top of each rod. Tighten with a screwdriver until the rods are held to the mirror but are still able to swing side-to-side.
Hold the mirror upright so that the support rods hang directly up and down. When they stop swinging, they will be exactly level. Attach brackets around the bottom of the support rods and install screws in both sides of the brackets. Tighten all of the screws as far as possible.
Measure the distance between the exact center of the support rods. Measure the length of the dresser and make a mark in the exact middle. Cut the distance between the support rods in half, then measure that far out from the middle of the dresser and mark it with a pencil.
Attach a bracket at each of the marks on the back of the dresser. Make sure the center of the bracket is on the mark. Install the mounting screws and tighten them as much as possible.
Attach brackets on the blind rail, directly below the brackets at the top of the dresser. Tighten the screws as much as possible.
Loosen the retaining screws in the center of the brackets. Hold the mirror over the dresser and slide the support rods through the brackets until it is at the desired height above the dresser. Tighten the retaining screws.