So you want to gain more members for your new founded GTUG and don't know that many people?
Some simple steps for more fame and potential members.
Hashtags that are interesting are
This will search for every tweet with the Words (Android/Java/Wave/Appengine) in it within 25 miles around Munich (where i work)
If you live in a suburban area you should increment the Radius to 50 or 100 miles.
Also use Identi.ca and Plurk for your search, Identi.ca is base on the OpenSource Microblogging System Laconia and has this nice Group Feature which could help eg http://identi.ca/group/android
Maybe you should write a short Presentation about your idea of a GTUG and spread them on http://www.slideshare.net
Go to Unconferences (BarCamps) and regular Group Meetings of other UserGroups and to all other TechEvents that are that you can find and that don't cost money.
Get a Site where you can describe your activities. You don't need a domain right now, you can do this later if it's needed. Setup your Base on Google Sites (http://sites.google.com) or Blogger or anything like this and get yourself an contactaddress that you redirect to your own email.
The name of your GTUG should be easy to remember, don't get caught on Acronyms. Its also ok to take the nearest Airport, they have quite good Codes like TXL (for Berlin Tegel, Germany) or MUC (for Munich, Germany) or JFK (JohnFKennedy, US)
There are more infos on that at the Start your own GTUG Site
Please remember: Always be polite, don't spam and be patient!