Using common materials, you can make some pretty nice handrails. I like to use spruce 2X lumber and rip the components to size instead of purchasing purpose made components. This allows me to get dimensions and scale to suit my liking. In this case, ripping the pickets to 1 3/4 inches. Additional components such as capping the rail with a 1x4 and trimming the edges with shoe molding turned upside down are simple ways to dress up this simple rail. You can also use beaded screen trim to cover the lower joint between the bottom-most 2x4 and the picket assembly. Small details like this make things more "architecturally considered" and less DIY. In the end, the rails will get caulked and receive a coat of solid stain. Up next is finishing the rails down the stairs, shingles, gutters and paint.