The first thing I always do is re-thread my top thread and re-thread my bobbin making sure they're correctly threaded. I have threaded my machine wrong multiple times without realizing it. Usually, this fixes my problem.
- Make sure you have the right type of needle for what you are sewing. For more information read my basics of sewing machine needles post.
- Make sure you have the right size of needle and right size thread for what you are sewing. These three diagrams show the importance of the right size of the needle and thread. When the thread is too large to fit in the groove, it can get damaged by the needle groove corners and it is not protected when going in and out of fabric. When the thread is too small, it flops around inside the groove.
- Change your needle for a newer one. Needles get old; they get dull and/or damaged so they don't work as well.
- If your thread is skipping, that means the shank on the back of the needle isn't deep enough and you might need a different size or type of needle. Read more about this in the sewing machine needles post.
- Reread your sewing machine manual about how to thread your top thread. I found that my manual says to have the spool unwinding in a counter-clockwise manner, but I didn't know this until I checked. Sometimes I still forget and have to rethread my machine.
- Try another brand of thread. I bought some spools of thread because they were on sale, but they mess up the tension on my machine meaning I can only use them in the bobbin.
- Don't use old thread. Thread gets weak overtime. Also, don't store your thread in the open, UV rays damage your thread making it weaker quicker.