@TheHappySpaceman
@LightningBolt
^^^
Typically, constructive criticism focuses upon that which appears to be a real issue. It very rarely has anything to do with opinion on a more general level; a lot more to do with real functions or techniques. A good example would be:
The file organization at the post office is very poor. You recognize this.
What do you do?
Non-Constructive Criticism
“Not one of you idiots can find the papers I need when I get here! I’d expect a serious establishment to have everything neat and orderly!”
Constructive Criticism
“I don’t mean to be intrusive, but I noticed that a lot of the files for customers, like myself, are in disarray. Everything else is great. I always love shipping or mailing with you guys. However, the file organization could do with a bit of work. May I recommend a few filing cabinets and portfolios, which would assist in keeping things together?”
Now, obviously if this was realistic, it’d be completely insane if the post office was in constant disarray. However, in this example you can see that non-constructive criticism doesn’t actually list anything that would help the situation, or even specifically what the issue is about. Constructive criticism usually mentions, specifically, what the issue or issues are and includes some way that these can be fixed or remedied. It helps to mention what the person or establishment is doing well, and then also mention what could use improvement, while giving them some words of encouragement.
With your situation, my words would go:
“You put a lot of effort and love into your work, and it shows it this piece. However, I find the anatomy of the legs to be off, in some way. The closest thing I can say is it looks like they’re switched. Now, maybe I don’t know what I’m talking about, but that’s just my honest opinion. Everything else about it looks fine, just the legs I feel are a bit off. I’m not really sure what one could do to change it, since I’m no artist myself, but that’s just my two cents. Keep up the good work!”
A major key point about constructive criticism is to avoid insulting someone in a way that is purely an insult. Perhaps your friend’s house does smell a bit odd, but if you’re wanting to say that to them, it’s best to say something along the lines of, “Does something smell a bit odd to you?”