A few suggestions for your first time:
Unless all of your group are experienced clubbers who don't feel inhibited about dancing and enjoying the club vibe, don't go to a club...remember, some people view clubs primarily as meat market opportunities, and quite frankly, that spoils the club experience imo. If any of your group are of that mindset, that's probably the mindset they will take into the experience, and that might affect the overall vibe of your group. I would suggest that you set up a house party so that nobody in the group will feel uncomfortable...that way, hopefully everyone will relax and get the maximum enjoyment.
Set up one room as the dance room...buy some black lights and any other visual aids (flourescent stuff works really well in black lights, obviously) that will enhance the experience. Set up at least one other room as a chill room with comfortable seating, pillows, etc., for people to relax and talk. If you have any music playing in the chill rooms, keep it downtempo at a lower volume.
As far as alcohol goes, I personally don't recommend it, but if you're going to have any on hand I would suggest red wine and maybe some champagne rather than beer or the hard stuff. Beer fills you up and gives you that bloaty feeling, and having the hard stuff around is too much of a risk that someone will get plastered quickly by pouring themselves stiff drinks. Wine or champagne is easier just to sip as you relax after you take the first one anyway.
Don't dissolve it in the alcohol...just take it whole, or half if that's what you've decided. Given that an average one doesn't contain that high a mg dosage anyway, you would probably maximize the experience by taking a whole one to start off...later, you can decide if you might want to take another half.
Have plenty of fluids on hand...water and fruit juices especially. My favorites are Sobe and Gatorade. Orange juice is also good. Pick up some candy too and put it out in a few bowls...tart candies are always fun to suck on.
Good luck...hope your experience is a safe and enjoyable one.