I'm sure some more experienced player will fill out this information but for what it's worth...
I think GAZ_UI is a mod which includes a load of useful features which should probably have been included in the origional game. These include
* Drag and drop build queue
* Display showing amount reclaimed
* Templates that work for all factions
* Loads of commands that you can assign to whichever key you want.
More info here...
http://forums.gaspowered.com/viewtopic.php?t=28817and here
http://wiki.faforever.com/mediawiki//index.php/GAZ_UIIt can be installed using the FAF mod vault (one of the tabs). I think you download and then enable in the Lobby.
It may also be worth mentioning hotbuild which uses GAZ_UI to provide an improvement on the built in "Build Mode". I really like this mod and feel lost without it these days. You can cycle through all factories by pressing 'w' or build mex with 's' and other good things like that. I believe it only works with GAZ_UI v4 (also in mod vault) and more info can be found here
viewtopic.php?f=41&t=2575I've had a few problems getting everything working but it's worth your time
Good luck!