Sensible advice there
In addition - make sure if you're planning an indoor trip you do the following:
1) Have all your music ready to go. It's very difficult selecting from 300 cd's during the peak - especially if you're getting fab visuals!
2) Unplug the phone, and take the batteries out of the doorbell! There's nothing worse than having your mother phone, or a neighnour pop round to borrow a casserole dish while you're blazing your tits off!
3) If its gonna be an all-nighter, keep your music at a sensible level. Neighbours banging on the walls can really freak you out when you're tripping.
4) Have a supply of munchies standing by, and be sure you have plenty of tobacco/cigarettes/skins etc - you might not be able to deal with a shopping trip! Products containing vitamin C are a good idea if things get a bit too much (or milk if you're on acid).
5) Make sure the environment is suitably ventilated - especially if you're gonna be burning lots of candles.
6) Make the environment pleasant and comfortable, with lots of interesting things to look at, play with, and trip out to. Hide any nasty things like bills, work reports, or anything that is likely to bring you down.
7) Most importantly, be with good people who you trust and make sure there is at least one experienced tripper in the group. Never trip alone.
If its going to be an outdoor trip:
1) Be in a location that you know, feel safe in, and are away from busy public areas.
2) Be very responsible about fires and other potential dangers. Enjoy the trip, but be aware that you are tripping. Jumping off mountains or going swimming in the sea are not good ideas! Climbing trees is fun, but not advisable as accidents can really put a damper on a good trip.
3) Be able to appear "normal" if a dog-walker or other "straight-person" happens by. If the police get called, it will almost certainly become a trip from hell!
4) Be suitably supplied with water, smokables, munchies, or anything else you may need.
5) Have coats and blankets standing by. Even in good weather, you can sometimes feel cold when tripping.
6) Be with sensible friends who you trust.
7) Be careful of your body. Outdoor trips can often lead to acrobatic feats that would not normally be attempted. Remember you are only human! Breakdancing in the woods is very funny, but the aches and pains when you come back down can last for several days!
Generally, have fun and enjoy the experience, but be aware and sensible (without obscessing) about basic health and safety, and common sense.
In a group situation, it is advisable for everyone to take the same dose at the same time. If people are comming-up and peaking at different times, it can lead to break-downs in communication that cause paranoid moments and potentially bad experiences. Look out for each other, and be ready to give a hug when needed. People are very vulnerable when they're tripping, and its just good practice to be aware of other peoples feelings!
Have at least 2 days clear after the trip has finished to let it settle. Going to work the morning after a trip can be very stressful and confusing.
The bottle can never be re-corked! Tripping changes you, and even after the trip is over, you're never the same again. Try to make it a constructive and spiritual experience. You can learn things about yourself while tripping that can be very useful in your ongoing process of personal evoloution.
(I'm just comming down after a particularly nice trip on the beach, seeing in the solstice sun rise. As a result, I have completely forgotten what I was going to say next! I guess I'll sign off now, and return when my short-term memory loss has abated! Lol.)