I have only done a tiny bit of morphing, so I cant offer much, but for starters, try to use pictures with big resolutions. The bigger the pic the better. That will make it a lot easier to work on detailed areas. Also when you are done editing a pic you will usually want to shrink it down to hide any blurry areas or anything else that might have gotten a little messy while morphing. The more you shrink it, the odds are it will be harder to see what you changed and look more realistic. That being said though, no one likes tiny pics, so if you could start off with something around 2000X2000 or more, and end up with something 700x700 that's not too bad. Bigger is better.