There's no one right answer to this. Firstly, you need to ensure that you buy and use feet that are designed specifically for your chosen machine, if you want to get the best results. Each model is different, and different feet will work better depending on the model you choose. In general, for upholstery projects, you'll need a cording foot or zipper foot, which helps with cording or welting, and a walking foot, which is helpful for those moments when you're working with multiple layers.