For a curved or irregular shape, the bandsaw is the best choice unless the piece is too large or you don't have a bandsaw then use the jigsaw; these tools will remove most of the waste. But the blades on these tools leave noticeable marks so don't cut on the line. The closer you cut to the line the easier it is to clean up the design to the line. This takes practice and a good saw. Then smooth the edges with either a sanding drum, router with a flush trim bit, or a hand planer or scrapper, work right to the line for a perfect shape like the edge of the bar stool below.