Adjust basting stitch setting on your sewing machine. Make a patch that is double the size of the unraveled area or hole in the garment. Cut rounded corners on the hole or patch to make the area strong enough. Turn the garment inside out and stitch the patch over the hole.
Now, set the machine to a zig zag stitch and position the hole / unraveled area under the needle of your sewing machine. Start stitching around the hole while not moving away from the edges of the patched area. Now, stop sewing and turn the garment over.
Lock the stitch by making back-stitch after you are done with sewing around the damaged area or hole. Now cut the thread and remove the garment from the sewing machine. Your garment is ready to be used again.
If you do not have a good sewing machine then you can also give your clothing to a professional. He or she will be well equipped with all the necessary tools and techniques to effectively fix any hole in your garments. However, they will cost a significant amount for their services so make sure that you really want to save your garment or just buy a new one. You can find professionals either online or in the yellow pages of your area.
These steps can also be done by hand if you find that your sewing machine is not up to par with handling a zig zag stitch. You can use a needle and thread to make a zig zag stitch by turning the garment inside out and working on the edge of the hole. You will want to close the hole with a clean zig zag stitch and then apply a patch neatly. You will want to take your time especially if you are not good at sewing.