Read http://www.codinghorror.com/blog/2008/08/quantity-always-trumps-quality.html where we repeat that doing the work results in better quality over being taught.
As to sufficient knowledge I think many fall for that and don't have anything to show.
I am planning on chaning caeers and I wish to retrain in IT. I did my fair amount on IT courses when in Uni but that was a long time ago, office, webdesign, graphic design, visual basic...what I want is to build eshops and also since I am a teacher educational websites, help schools load the homework online courses etc. I want to study moodle and magento or joomla but I wish to know if that would be sufficient to find work in that field ? what else would you recommend? thank you so much for your help