You can combine yarns to get different weights. If you need a sport weight yarn... combine two fingering yarns. If you need a worsted weight yarn... combine two sport yarns. If you need a bulky  yarn... combine two worsted weight yarns. Always check your gauge, but many times this is a great way to use up extra yarns you have.

When sewing buttons on your garments that have been knitted,  use elastic thread, not yarn. You can purchase it at fabric stores and your buttons won't pull on the knitted fabric or cut the yarn after wearing several times.

To ward off moths, put small chunks of Irish Spring bath soap with your wool.

Leave shoulder stitches on needles or stitch holders instead of binding off. When back and front are completed, knit together and bind off at shoulder seam. Seam is smooth and flat.

When joining a new skein of yarn, knit 3 stitches using both the end of the old skein and the beginning of the new skein. Drop old skein, and continue with new skein.