First, decide what sort of group you want to have. Do you want your club to be open to everyone, or would you prefer a more elite, invitation-only set up? Would you like to hang out listening to old Dead shows, go to live jam band performances, or organize massive music swaps? Think about what you want to do and who you want to do it with.
Next, think of a name for your club. Look to Dead band members, history, lyrics, symbols, and song titles for inspiration. Make sure the name is catchy and not too cumbersome, easy to spell and say out loud. It doesn't hurt if the name looks cool written out, too—you never know when you might want to create a club t-shirt or other paraphernalia!
Finally, get the word out about your club. Advertise online via social networks and forums, and consider using a site like meetup.com or a group email service such as yahoogroups.com to help you get organized. Make flyers or postcards and ask around at local record stores, coffee shops, smoke shops, and other friendly venues to see if you can leave your info for anyone who might be interested.
Your club will be as good as you make it. Be sure to have some sweet Grateful Dead music, plenty of snacks, and fun conversation starters on hand, and get ready to have a great time.