To be honest it feels like you're trying to be a designer.
A lot of what I see is a collection of icons and effects that are just 'put' together. Effects for effects sake look artificial and show up weak design skills.
Without understanding the brief you were working to, it's also difficult to appraise.
I would say that a lot of your illustrations would benefit from less black and removing keylines from type would also help - unless that is truly your style.
I would also try taking some of the illustration-only work and including it in some kind of poster or design where the illustration reinforces some kind of message. Illustration is rarely used just for a pretty picture.
Off the top of my head, try taking one of the butterfly-based images and incorporating it into a flyer for a girly, fashion boutique.
Look further at the typefaces you use - Impact or whatever condensed Helvetica lookalike you are using looks a bit flat.
Hope this helps.
Paul