LSD is a very powerful drug. It's not something to take just on a whim, it needs to be planned out. What do you plan on doing during this time? Will you be in a safe, comfortable environment? Are you in a good state of mind as of late? These are questions you must ask yourself for the best possible experience.
Everyone is different, however being someone who has tripped around 30 times, I'd like to think I have experience in the subject. I personally don't like taking LSD in large groups, especially if you're meeting people for the first time. You said you will be doing some drinking, that is perfectly fine as long as you're not drinking to get drunk. Preferably I like to chill out with 2 or 3 beers throughout my trip, it helps me relax and I know it won't get me drunk. Being drunk is not fun when you're tripping, it just makes you feel sluggish and takes away from the experience.
Environment is very important for a first timer. Make sure you have at least 8 hours of time to spare, and are in a safe and comfortable environment. You don't want to dose at a friends house, only to find out you have to leave 3 hours into you're trip. You'll want to dose, and sit down knowing you can sit in that spot for as long as you want, knowing you have nothing to worry about.
Bad trips are a result of not thinking things through, and allowing yourself to get wrapped up in a single negative thought, usually resulting in you spiraling out of control. Whenever I start feeling anxious, I remind myself that I dosed myself, and it's only a chemical, it will eventually leave my body and my state of mind with eventually revert back to normal. I like to remind myself, even if I was having the best time, as oppose to the worst, it wouldn't last forever, even if I wanted it to.
Remember, have at least 8 hours to spare, 8 hours at the least. Be in an environment where you know you are safe and not in harms way. Surround yourself with people you trust and know are friends. And most importantly, remember it's only a drug, it's just another chemical. When in doubt, put on some music and close you're eyes, and allow you're body and mind to slip away. That is the key to having a good experience, allowing you're body and mind to slip away from reality.