I don't really go out that often, but when I have done I can tell you this; 9 times of 10 the evening is incredibly dull. It seems everyone's sole intention is to get drunk...and to be it seems rather pathetic and pointless. I know how you feel when you say about people ignoring you. Even when I make the effort to speak to people, they always seem to want to talk to others rather than with me. I've never been approached by someone during a party/night-out. In regards to the ladies; I don't understand it either dude.
I'll give you a brief overview of my last two outings which happened last week;
1) Went to the pub. Everyone was having a chat and a drink (as you do). Most of the evening I spent listening to the conversations of others, occasionally chipping in and making people laugh. I don't think anyone made an effort to have a conversation with me that entire evening, other than the odd comment/question or two.
2) Went to a party. "Experimented" with drinks so was a bit tipsy and slightly more confident than usual. Decided to use said confidence to try out some things people have suggested me to do on here. Approached girl I hadn't seen for 2 years, conversation lasted 2 minutes (though I did get a kiss on the lips

). Spoke to some guys as well which lasted about 30 seconds. Everyone I didn't know well basically ignored me or didn't want to speak to me.
Unfortunately people are like that; I've never understood it either. One thing I won't ever do is change myself to be accepted by others.
Sorry I can't be of much help to you mate...just wanted you to know that you're not alone really.