When it comes to streamlining your workflow there are lots of little things that you can do to help your overall process. The EXIF data contained in your image files if used wisely can certainly be a great little time saver.
Gallery 2, like a lot of other image galleries can read your EXIF/IPTC data and put it to good use. This will make the process of uploading multiple images much quicker and easier by automatically applying: Titles, Descriptions and Keywords to your images without the need for any intervention afterwards. This is done from the Library module within Adobe Lightroom.
Apply your keywords> tags to you image. Or, to make things easier use an existing a keyword tag set, or create a new one to speed up the process. These keywords correspond to the keywords within Gallery 2.
Lightroom - Keywords
Apply the image Title and Caption - these correspond to Tile and Description Fields within Gallery. The easiest way is to ensure that you select the Quick Describe view within Lightroom.
Lightroom - Title and Caption
Make sure that you have the EXIF/IPTC Plugin installed and configured within Gallery 2. The setting that I have selected will produce the required result of automatically populating the Title, Keywords and Description. If you are using IPTC/EXIF it will override your settings during upload.
Gallery 2 - EXIF/IPTC Configuration
From within Gallery you should now have the information we set above applied. How Gallery 2 uses this information will depend on the Gallery 2 theme and configuration.
Gallery 2 - Edit Item