The best angle from which to draw a bag to show its design details to the best effect is the three-quarter view. Start with a cube or cylinder, whichever is closest in shape, then add shading and design details.
Begin by drawing twenty ovals. Divide a piece of paper into four sections. Choose four bags from your wardrobe or find reference photos of your favorite bags. Draw each of them carefully, paying attention to the materials they are constructed from and how shadows form on them and light is reflected. Work slowly and with great precision so you will have a piece good enough for your portfolio.