The following can go one of either two ways: 1. Your friend has actually created something wonderful, or even pretty good, leading to feelings of jealousy, inadequacy, etc. Now, that is a tough thing to deal with as well. But more likely you’ll be handed 2. It is not wonderful or even slightly good. It may be completely terrible. Then what the hell do you do? Well, obviously there are many factors, like how close you are and how sensitive they may be, but as a general rule of thumb, first thing to do is figure out a rating.
Rating: 4.5-5 Stars
You tell them the truth. They did a great job and should be congratulated. Maybe suggest a few ways to polish it if you want, but try to communicate that you really did enjoy it and hope when you hand them something of your own they feel the same way.
Rating: 3 Stars
Okay, there are some issues. You see the issues, and some are pretty glaring. But there is a lot of good. Find at least three details you can genuinely defend as something you enjoy. Bring those up right away along with a congratulations that they’re so close to being done. It’s important to keep it clear that you think it needs more work (if it can still be worked on) but that you really see where it’s headed. Try to gently, constructively nudge them in the right direction. If they honestly wanted your input then you owe them honest feedback.
Under 2 Stars or Less
Is there anything good? Anything at all? After you compliment them on doing something, anything, mention how much you really like whatever thing that was good, no matter how small. Then you should probably change the subject. And this isn’t only to avoid that awkward moment or to not risk coming off like a jerk — if you think their work is that bad, you either have to tell a friend they created a bunch of junk, which probably won’t be good for anyone, or you need to try to get them to overhaul the whole thing. You’ll need to offer a bunch of notes, list some tricks and tips and maybe get in there and do some tinkering yourself to put them on the right track.
Don’t do this. You may think you’re helping, but you’re actually taking their own creation away from them. Your friend is not Vermeer or Arbus or Lennon or Faulkner. But they created something they liked and were proud of, enough to show it to you. Yeah, maybe it sucks. But it’s theirs and it should stay that way.