1. Glasses - these can make a huge difference. If you are starting a wine club, then ISO tasting glasses are ok. Otherwise Riedel glasses are fantastic - you don't need the expensive ones, as the cheap ones have similar shaped bowls and are great value for money. One great trick is to have a tasting with Riedel glasses and your usual glasses. You will be stunned.
2. Budget for about 11-12 people per bottle. We normally do about 10 wines in an evening. At these amounts, you don't go away pi**ed by wine number 4.
3. Make sure you have some water, biscuits and cheese available to clean the palate in between wines.
4. If you're doing it right, don't go for cheap wines. We manage on a budget of 15 USD per tasting of 10 wines to do up to 10 wines up from 18 to 70 USD per bottle. Make it special!
5. Keep the tasting focussed - say Californian Pinot Noir, Loire Valley, Red Bordeaux emphasising 'left' v 'right' bank, burgundy, Piedmont or Tuscany in Italy, Argentina etc.
I belong to a wine club in the UK that's been going for over 20 years. Once you get going, it's great fun; you will never get to know everything about wine - ever!!!!