1. Be sure needle and thread and fabric are compatible. Right size needle, thread content and wt and is fabric 100% cotton or a combination.
2. Always use a new needle on a new project.
3. Clean bobbin area and oil where manual indicates.
4. Re-thread needle and bobbin.
5. Hold both needle and bobbin threads for several stitches.
If doing all of the above fails, it time to take machine in for repair! I hate it when this happens, but in my case it is usually operator error! Don't give up.