Usually, I'm making the migrations locally with xampp or mamp pro, and install locally the old DB as well. That is the way it work the best for me.
The templates are also prepared for Joomla! 3 (templateDetails.xml) and put in /tmp, so it is easy the control, correct and install them.
I just had lately a tiny problem with Joomla! 3.3.1 and the support was fast and good.
Of course, one has still to understand MVC concept but EasyCreator is a big help for starting to write an extension.