While I'm not very experienced in moccing in general, I thought I'd share a couple pieces of advice that don't seem to be here, as well as see if you guys have any ideas one the subject of weapons.
First off, I've found I do my best work (such as it is) while listening to music. Finding some good music to listen to while you moc can help a lot.
I also find looking at things other than bionicles can help when it comes to inspiration. For example, I just finished making a WH40K chainfist, and there really wasn't a lot of lego-based reference material for that
Speaking of weapons, does anyone have any advice on weapon construction? I've found I'm better with weapons than the mocs themselves as of now, but it's always good to have more ideas!