Are you linking the old domain to the new one, that will keep the old ranking up there while dragging the new one up. Pretty simple really, you transfered your content but nothing else. Transfering your keyword popularity takes time. Seriously it does.
You seem to know what you are doing, try to keep the website as simple to use as possible that's the main thing. Google rates rentention rates as well as keywords.
Keeping your users on the page and getting repeated searches on Google is getting more important than having your keywords in your meta tags right.
Go through your whole page and look for broken links. Also google runs through websites looking for using too many div tags. Negative effect. That used to be acceptable, not any more. Google has been updated, your website has not.