I too lift the presser foot every so often and go as slow as you can, especially for a very curved seam. Practice on scrap fabric until you get the hang of it.For inside or outside curves, the trick is watching the seam allowance where the knife is cutting rather than at the needle as you would with a conventional machine. Otherwise guide the fabric as you would if straight stitching.
Practice makes perfect. Curves were difficult for us at first, but now they seem easy. When the seams are quite curved, lift the presser foot every few inches and turn the fabric under it.