Something we should point out is that if you arrange to meet someone 'from the internet' then they might not be exactly who they told you they were, and their motives MIGHT be suspect.
Please be very careful when you arrange to meet someone for the first time. Make sure the first meeting is in a public venue - DON'T JUST TAKE ANYONES WORD FOR IT THAT A VENUE EXISTS. Do some research for yourself, and make sure that a club exists, that it is what it is supposed to be and it will be open for the public at the time you intend to meet.
If you are intending to meet one person instead of a group, then the problem of deception becomes greater:-
ALWAYS make sure you speak to the guy on the phone before you agree to meet. The sound of their voice might mean you won't be meeting any middle-aged perverts.
ALWAYS take a fully charged mobile phone
ALWAYS have the means to get home safe about your person - a return train ticket in your shoe for example.
ALWAYS leave a note with a responsible friend or parent as to EXACTLY where you are going and who you are meeting.
ALWAYS arrange to call that person at a pre-set time to tell them you are okay. Use a secret code word to tell them that things are proceeding as planned. For example, if you use the word 'coffee' at any point in your message then things are fine, but if you use the word 'uncle' then you are in trouble and your phone buddy should call the police. So, "Did uncle David get back all right?" is a request for help that you can make even while you are being overheard by someone you distrust.
ALWAYS be a little paranoid. Ask yourself "Why do I have to walk through this underpass to get to the meeting place? Is someone gonna mug me and take all my minis?"
Think tactical. Don't put yourself at any disadvantage, not ever.