One of the best ways to finish a garment so that it looks handmade rather than ‘homemade’ is to use hand stitching for hems, facings and other final steps. I thought about doing some tutorials, but there are so many already out there, so I just rounded up some links for you 
BTW, my favorite stitch for hemming is the catchstitch, very easy and secure!
oliver + s blog- blindstitch and catchstitch
Otis Fashion Studio video- basting and catchstitch
futuregirl craft blog- blanket stitch (good for kids’ appliques)
Pins and Needles blog- prick stitch (for understitching a lining and putting in zippers by hand- the only way for me!)
Instructables- slip stitch (for closing linings in bags or anything that is stuffed)
Hope this list gets you started! As always, great resources on sewing are heirloom patterns and books.
