The best suggestion I can give you is to try to model actual objects or scenes. Learn how to do that. If you have your heart set on abstract, then dont do the spikey-wtf-is-that-omg-its-coming-at-me-random-brushing-explosion trendwhore kinda stuff. Figure out your own style for abstract. Heres a few examples:
http://www.deviantart.com/view/14357726/
http://www.deviantart.com/view/9351913/
http://www.deviantart.com/view/8449669/
http://www.deviantart.com/view/8483242/
http://www.deviantart.com/view/9150545/

I still suggest learning to model real objects. Thats what I'm doing and modelling real objects is the best kind of 3d