dmrlook has the right idea. Move what you can to the SD card, and use web apps as often as possible. I don't have Facebook installed, for example. I just use the mobile website for it.
Google+ is a giant space hog and very little of it transfers to the SD card. Drop it and use the browser.
Someone will no doubt pop in here and tell you to use Titanium Backup or something. Don't listen to them. If you've moved everything manually, there's not much else you can do except be very selective in which apps you really need on your phone.