Decide how tall and wide you want your shutters to be. Each shutter should be two to three boards wide. Shutters were originally used to control light and protect window openings from harsh weather. Two shutters would cover the entire window or door. Keep that in mind when creating your design.
Use your saw to cut the vertical boards to length or have your local home improvement store cut them for you. You'll also need to cut two 1x2 cleats for each shutter (those are the horizontal pieces). The length of the cleats will depend on the finished width of your shutters. Cleats can be slightly smaller than the overall width.
Work on one set of shutters at a time. Assemble your boards on a clean, flat surface. Lay the boards side-by-side, but leave a small ¼-inch to ½-inch gap for expansion (especially important if they are to be exterior shutters).
Lay the cleats horizontally across the boards. You'll want one cleat toward the top and one toward the bottom on the shutter. Eyeball the spacing and use what feels right. There's no right or wrong to the design.
Pre-drill through the cleat and shutter boards. Each board should have one to two screws. Use glue between the boards if you want to see fewer screws.
Drill in the screws, attaching together the cleat and shutter board.
Paint and decorate your shutters. Use faux painting paint techniques to get a aged feeling you want for your rustic shutters. Or leave the boards to weather naturally.