Wood blinds are a nice touch to a window treatment. They typically have large wooden slats and head rails, along with brackets that mount to the top window trim and the head rail. However, it is possible to hang a wooden blind to the top window trim without the use of brackets. This will give you a cleaner look. It also eliminates the slight gap between the backside of the blind and the window trim caused by the brackets.
Drill two holes through the face of the head rail approximately 1 inch inward from each end. Use a portable drill and a drill bit large enough to allow the screws to slide through the head rail. This will prevent the head rail from splitting when you drive the screws into the wall. Inspect the ratcheting mechanism at the top of the head rail. If you can add a third screw hole through the centre face of the head rail without damaging the ratcheting mechanism, do so. This will add additional rigidity to the mount.
Place the head rail over the top window trim and centre it over the window. Place a bubble level on top of the head rail and position the blind so it remains level on the top window trim. Mark the holes you drilled onto the head rail by placing a screw into each hole then pressing the screws into the wood. This will give you an indentation.
Drill pilot holes into the top window trim with the drill and a drill bit approximately half the size of your screws. Drill the pilot hole 1-inch deep.
Place the head rail over the top window trim and centre the rail over the holes. Secure the head rail to the window with 2-inch drywall screws. Drywall screws are black and tend to blend in with wood finishes. You can substitute these screws for a different variety; however, they must be long enough to go through the head rail and into the top window trim by at least 1 inch.