Finishing your knits can make a big difference to how they look. It sounds intimidating but really it's just about putting the finishing touches on a knit so it looks as well as possible.
Here are the basic steps and you can find more detailed tutorials on each in the links:
- Seam your knit using Mattress Stitch if it was knit in pieces.
- Weave in all ends on the wrong side so that they are invisible on the front of your work.
- Block your knits to smooth out the stitches using the technique that best matches the knit type.