I learned by posting stuff on a forum I was on at the time and having people explain to me what needed work, and then working on it for the next piece (because if I kept fixing everything that was wrong with stuff I'd posted unless it was a wip I specifically needed help on, I would never get anything done).
So rather than bin things that aren't working, either post them and ask for help or do what you did and drop them in Artbees and ask for help :)
Okay well feel free to bin some things that really aren't working, sometimes you embark on what seems like a good idea at the time and then you just don't feel it after a while (which is pretty much what's happening with that sketch I posted in my last progblog, I did a few more flats today, then looked at it and was like really should finish it just so I have concept art of these two but...nup).
What do you mean you've got a community left to chat on :O
Well I am in several communities but most end up me lurking on them with no topic to connect with. I pop in to see what's up and then move to another server to rinse and repeat. I do that to ArtBees too but I find myself more chatty there.
If I stop and continue later there's a greater chance I would abandon it afterwards. So I just end up working on it for hour with breaks just leaving it minimized trying to break the habit of not abandoning too early and push.