Sometimes it's a matter of tailoring your approaches and modifying your goal based on the social situation. Picking up girls at a singles mingle is entirely different than at a hopping club or at the library or on social media. I'm a believer in trying to see yourself through the eyes of the women you're trying to pick up. Try to understand their goals, motivations, and anticipate their resistance so you can know how to tailor your game to be more effective.
Although it's obvious you aren't going to be successful in every case, you can increase your odds.
Let's take a look at the social situation. It's a singles mingle where girls are in sets. It's not a crazy party or club... Girls aren't going to be getting drunk, dancing in cages and grinding on strangers. There's an expected level of decorum socially. So the chance of you isolating a girl from her group in some dark corner and making out and her friends not miss her is very low.
Also take a moment and imagine what is motivating these women. They aren't likely looking to party, get crazy, and have a wild night. I'm guessing these women are all looking to find that well-off handsome nice guy that is in all their romance novels, and the goal is to get him before their friends and all the other girls get him. If he's not there or he's already taken, most will go to "power down" mode.... Unless something else happens.
That's where we come in. We aren't what they came to that place for. But it's our "job" to swoop in, be charming, well groomed, fun, entertaining, aloof, and trigger something sexual inside them, all the while giving them something to chase. We offer them that irresistible fantasy. That's why things like value, push pull, cat string theory, negs, and time constraints work.
Let's break down your above encounters.
1) you opened well then the girls wanted to break off and check out the scene. Why do you think that was? If Brad Pitt was the one they met as they entered, would they have broke off like they did with you? Why not? Because of VALUE. Brad Pitt would be an instant 10 value and every girl knows it. They will spend the rest of the night trying to increase their value to him. They left you to assess the value of the rest of the guys there. Unless you had built in value, your best line isn't going to keep these girls from exploring and assessing the value of every other guy there. That's what a single mingle is for most women - find the highest value guy then compare their own value to his and respond according to their own goals. If her goal is a new BF and his value is higher than hers and he shows interest in her and "speaks the language" there's a good chance things will progress. If she doesn't find anyone with a value higher than hers, chances are she's just gonna chat with her friends and gossip and complain about the lack of cute guys at the mixer! If there is a higher value guy who seems interested in another girl, that's where the fun happens! Anyway, that's what happened here. They probably have you a decent initial value but checked out the scene, kept an eye on you, didn't see you raise your value and found others they felt had higher value. If during that time you increased your social value I suspect one of them would have been receptive at a reopen.
2) Perfect example of value! Blonde with nice tits... Take a moment to imagine how many times she's been hit on (weak or otherwise). Say it's as low as once a day (probably much higher) but even at that, that's hundreds of times a year and many thousands over her lifetime. Women like this have high value in their mind. You standing there talking to her simply entertained her, increased her value to all the girls at the table, then she cut you off when she knew you weren't going to outvalue her. In that moment when she ignored you, what do you think she would say her value was versus yours? She was in it for the ego boost and she got it! Everything from this encounter was stacked against you. High value target surrounded by her adoring lower value friends. Were they sitting at a table and you standing there talking? I couldn't tell but that's a terrible situation to open in. You are an outsider, easily pushed out which seems like what happened. You want to become the center of attention opening sets, not simply standing on the sidelines. Only chance here with that blonde would have been to take control of the set from her, increase your value while decreasing hers, then keep her trying to gain it back while entertaining the set and ignoring her. Even then it's tough in this situation. That's why identifying your surroundings and assessing the social situation can help. May have been better to use this set to demonstrate value to other sets watching you by swinging by, opening the set, get them laughing and having fun, then bail out with them wanting more. Other girls will see that and think "that guy just left all those girls just when he had them where he wanted them - who does that?" A PUA does, that's who! And they're going to want you to get them laughing and having fun too.
3) You hit on a girl, she leaves then you hit on her friend? Girls can pick up on this really easy. Usually shows you're just hitting on whoever is in range and shows desperation. Now if she IOIs you when her friend leaves, that's another story. But more than likely she saw you as just jumping from girl to girl trying to get lucky... Which isn't too far off the truth now, is it? Better off in a set either picking one and sticking to her or don't pick any and see who gives IOIs first. Remember, what would a high value guy do once he's "chosen" his interest? Since he knows he is high value, he's going to get the one he picked and not "lower" himself with anyone else - at least that's what you need to portray for now... Until another girl steps up and tries to increase her value to you!
4) this one is simple. Again, value. By this time you've been there all night and these workers surely have seen you striking out all night, lowering your value. When you finally got around to them what do you think they thought of you? Now again imagine Brad Pitt has been hanging out with the hottest girl all night, stepped away from her and walked over to this girl who was working and said "I've been waiting all night for a chance to introduce myself to you".... How would have she reacted? Now what if it wasn't Brad Pitt but instead it was the guy with the highest value of the night. It would be the same! This is because women in these social gatherings are constantly observing and adjusting values of the guys. That natural alpha male who's spent all night as the center of attention and increasing his value... When he walks over to that hot 10 he's ignored all night and says he's taking her home... Yeah that happens... A lot!
1) Assess the situation and tailor your approaches accordingly.
2) Be mindful of your value always. Learn and execute ways to increase your value in every situation.
3) Set a goal and approach based on that goal.
4) Increase your skills until this becomes second nature.
Ok, I think we have some advice here.
1- I agree a lot with your analysis on the first two women who entered. I didnt think I did anything wrong with my opening. Its just they wanted to explore the place. Now the question is, how on earth for me to increase my value ?
2- blonde with big tites, to get this straight, you think i should have advertised myself as a high value guy BEFORE approaching her ? So they would be the girl whom I was ignoring her all the time.
3- Chicken and Egg problem: Why would any girl give me IOI if she didnt think I was high value ? And how could that happen with me just standing there and being the guy who has his" pick" and only chooses the one he likes? I thought demonstrating social power by "hitting on" every girl increases my value?
Overall, very good advice. Whats your story with Pick-up ?