I haven't been as active lately partially because I have been intensely practicing and busy, but I pop my head back into the forum every so often. Anyway, as of recently, I have found a major issue for most younger PUAs and I would like to start a discussion in regards to this.
The issue:
In the United States, a majority college girls can not go to most clubs or bars until they are 21+. This makes it extremely hard to have a second meet up with a girl who is under 21. Particularly in my area however, there are many fraternities and different colleges that girls like to party at. I have identified the issue to this problem- girls always go along with their social circle of girl friends. Even if you invite their entire social circle to a party that you are hosting, they generally have plans for the night with their friends (Eg. "Sorry I would really love to go to your party, but my friends are all going to go to a party at [XXXX College]. Otherwise I would totally go!") Please don't say this is relative to attraction or comfort because girls are attracted enough to text me randomly at times. Girls are just going along with their friends nonstop. All it takes is 1 or 2 girls out of a group of 10 to influence the entire group. At times I have in fact got many social groups to come out to my parties. Girls always consider the option even if they may not follow through. There are always road blocks that I cannot get through at times though, including existing plans, one girl in the group who is "sick" or is the party pooper who wants to "go to the other party." I'm not really sure but there is always dumb girl shit like that. My final issue is that I constantly revert to somewhat of an AFC trying to get these girls to come out. I begin texting or calling these girls 2 or 3 times a week to find a good time to meet up. At times when no girls are available I may even try to communicate with these girls even more (never more than 4 times a week). Not that it is a necessarily a bad thing texting a girl 1 or 2 times every week, I am just going to seem needy if I text a girl more than 2 times per week. It is just very hard finding a good time to get a girl to come out with me because many times, younger girls are bad at making plans or have existing plans. 
So basically I need some advice:1. If a girl is sufficiently attracted, how do I get her to come out, avoiding the road blocks that are out of a lot of guy's control?
2. How can I figure out a good time to meet up limiting myself to maybe 1 text or call per week?
3. Any strategies to get a girl to come out only sending 1 text or phone call?
Thanks guys... Please keep it positive and I always appreciate your help!